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603 lines
18 KiB
C
603 lines
18 KiB
C
/*
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* Mesa 3-D graphics library
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* Version: 7.1
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*
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* Copyright (C) 1999-2007 Brian Paul All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
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* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include <precomp.h>
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/* Stencil Logic:
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IF stencil test fails THEN
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Apply fail-op to stencil value
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Don't write the pixel (RGBA,Z)
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ELSE
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IF doing depth test && depth test fails THEN
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Apply zfail-op to stencil value
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Write RGBA and Z to appropriate buffers
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ELSE
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Apply zpass-op to stencil value
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ENDIF
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*/
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/**
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* Compute/return the offset of the stencil value in a pixel.
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* For example, if the format is Z24+S8, the position of the stencil bits
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* within the 4-byte pixel will be either 0 or 3.
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*/
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static GLint
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get_stencil_offset(gl_format format)
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{
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const GLubyte one = 1;
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GLubyte pixel[MAX_PIXEL_BYTES];
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GLint bpp = _mesa_get_format_bytes(format);
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GLint i;
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assert(_mesa_get_format_bits(format, GL_STENCIL_BITS) == 8);
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memset(pixel, 0, sizeof(pixel));
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_mesa_pack_ubyte_stencil_row(format, 1, &one, pixel);
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for (i = 0; i < bpp; i++) {
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if (pixel[i])
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return i;
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}
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_mesa_problem(NULL, "get_stencil_offset() failed\n");
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return 0;
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}
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/** Clamp the stencil value to [0, 255] */
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static inline GLubyte
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clamp(GLint val)
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{
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if (val < 0)
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return 0;
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else if (val > 255)
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return 255;
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else
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return val;
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}
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#define STENCIL_OP(NEW_VAL) \
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if (invmask == 0) { \
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for (i = j = 0; i < n; i++, j += stride) { \
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if (mask[i]) { \
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GLubyte s = stencil[j]; \
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(void) s; \
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stencil[j] = (GLubyte) (NEW_VAL); \
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} \
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} \
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} \
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else { \
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for (i = j = 0; i < n; i++, j += stride) { \
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if (mask[i]) { \
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GLubyte s = stencil[j]; \
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stencil[j] = (GLubyte) ((invmask & s) | (wrtmask & (NEW_VAL))); \
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} \
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} \
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}
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/**
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* Apply the given stencil operator to the array of stencil values.
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* Don't touch stencil[i] if mask[i] is zero.
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* @param n number of stencil values
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* @param oper the stencil buffer operator
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* @param face 0 or 1 for front or back face operation
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* @param stencil array of stencil values (in/out)
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* @param mask array [n] of flag: 1=apply operator, 0=don't apply operator
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* @param stride stride between stencil values
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*/
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static void
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apply_stencil_op(const struct gl_context *ctx, GLenum oper,
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GLuint n, GLubyte stencil[], const GLubyte mask[],
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GLint stride)
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{
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const GLubyte ref = ctx->Stencil.Ref;
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const GLubyte wrtmask = ctx->Stencil.WriteMask;
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const GLubyte invmask = (GLubyte) (~wrtmask);
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GLuint i, j;
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switch (oper) {
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case GL_KEEP:
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/* do nothing */
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break;
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case GL_ZERO:
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/* replace stencil buf values with zero */
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STENCIL_OP(0);
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break;
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case GL_REPLACE:
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/* replace stencil buf values with ref value */
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STENCIL_OP(ref);
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break;
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case GL_INCR:
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/* increment stencil buf values, with clamping */
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STENCIL_OP(clamp(s + 1));
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break;
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case GL_DECR:
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/* increment stencil buf values, with clamping */
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STENCIL_OP(clamp(s - 1));
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break;
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case GL_INCR_WRAP_EXT:
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/* increment stencil buf values, without clamping */
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STENCIL_OP(s + 1);
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break;
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case GL_DECR_WRAP_EXT:
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/* increment stencil buf values, without clamping */
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STENCIL_OP(s - 1);
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break;
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case GL_INVERT:
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/* replace stencil buf values with inverted value */
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STENCIL_OP(~s);
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break;
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default:
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_mesa_problem(ctx, "Bad stencil op in apply_stencil_op");
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}
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}
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#define STENCIL_TEST(FUNC) \
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for (i = j = 0; i < n; i++, j += stride) { \
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if (mask[i]) { \
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s = (GLubyte) (stencil[j] & valueMask); \
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if (FUNC) { \
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/* stencil pass */ \
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fail[i] = 0; \
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} \
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else { \
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/* stencil fail */ \
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fail[i] = 1; \
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mask[i] = 0; \
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} \
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} \
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else { \
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fail[i] = 0; \
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} \
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}
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/**
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* Apply stencil test to an array of stencil values (before depth buffering).
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* For the values that fail, we'll apply the GL_STENCIL_FAIL operator to
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* the stencil values.
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*
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* @param face 0 or 1 for front or back-face polygons
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* @param n number of pixels in the array
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* @param stencil array of [n] stencil values (in/out)
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* @param mask array [n] of flag: 0=skip the pixel, 1=stencil the pixel,
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* values are set to zero where the stencil test fails.
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* @param stride stride between stencil values
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* @return GL_FALSE = all pixels failed, GL_TRUE = zero or more pixels passed.
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*/
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static GLboolean
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do_stencil_test(struct gl_context *ctx, GLuint n,
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GLubyte stencil[], GLubyte mask[], GLint stride)
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{
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GLubyte fail[MAX_WIDTH];
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GLboolean allfail = GL_FALSE;
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GLuint i, j;
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const GLuint valueMask = ctx->Stencil.ValueMask;
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const GLubyte ref = (GLubyte) (ctx->Stencil.Ref & valueMask);
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GLubyte s;
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/*
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* Perform stencil test. The results of this operation are stored
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* in the fail[] array:
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* IF fail[i] is non-zero THEN
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* the stencil fail operator is to be applied
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* ELSE
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* the stencil fail operator is not to be applied
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* ENDIF
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*/
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switch (ctx->Stencil.Function) {
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case GL_NEVER:
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STENCIL_TEST(0);
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allfail = GL_TRUE;
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break;
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case GL_LESS:
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STENCIL_TEST(ref < s);
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break;
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case GL_LEQUAL:
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STENCIL_TEST(ref <= s);
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break;
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case GL_GREATER:
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STENCIL_TEST(ref > s);
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break;
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case GL_GEQUAL:
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STENCIL_TEST(ref >= s);
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break;
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case GL_EQUAL:
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STENCIL_TEST(ref == s);
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break;
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case GL_NOTEQUAL:
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STENCIL_TEST(ref != s);
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break;
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case GL_ALWAYS:
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STENCIL_TEST(1);
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break;
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default:
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_mesa_problem(ctx, "Bad stencil func in gl_stencil_span");
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return 0;
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}
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if (ctx->Stencil.FailFunc != GL_KEEP) {
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apply_stencil_op(ctx, ctx->Stencil.FailFunc, n, stencil,
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fail, stride);
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}
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return !allfail;
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}
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/**
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* Compute the zpass/zfail masks by comparing the pre- and post-depth test
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* masks.
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*/
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static inline void
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compute_pass_fail_masks(GLuint n, const GLubyte origMask[],
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const GLubyte newMask[],
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GLubyte passMask[], GLubyte failMask[])
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{
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GLuint i;
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for (i = 0; i < n; i++) {
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ASSERT(newMask[i] == 0 || newMask[i] == 1);
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passMask[i] = origMask[i] & newMask[i];
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failMask[i] = origMask[i] & (newMask[i] ^ 1);
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}
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}
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/**
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* Get 8-bit stencil values from random locations in the stencil buffer.
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*/
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static void
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get_s8_values(struct gl_context *ctx, struct gl_renderbuffer *rb,
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GLuint count, const GLint x[], const GLint y[],
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GLubyte stencil[])
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{
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struct swrast_renderbuffer *srb = swrast_renderbuffer(rb);
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const GLint w = rb->Width, h = rb->Height;
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const GLubyte *map = _swrast_pixel_address(rb, 0, 0);
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GLuint i;
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if (rb->Format == MESA_FORMAT_S8) {
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const GLint rowStride = srb->RowStride;
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for (i = 0; i < count; i++) {
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if (x[i] >= 0 && y[i] >= 0 && x[i] < w && y[i] < h) {
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stencil[i] = *(map + y[i] * rowStride + x[i]);
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}
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}
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}
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else {
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const GLint bpp = _mesa_get_format_bytes(rb->Format);
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const GLint rowStride = srb->RowStride;
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for (i = 0; i < count; i++) {
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if (x[i] >= 0 && y[i] >= 0 && x[i] < w && y[i] < h) {
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const GLubyte *src = map + y[i] * rowStride + x[i] * bpp;
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_mesa_unpack_ubyte_stencil_row(rb->Format, 1, src, &stencil[i]);
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}
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}
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}
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}
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/**
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* Put 8-bit stencil values at random locations into the stencil buffer.
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*/
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static void
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put_s8_values(struct gl_context *ctx, struct gl_renderbuffer *rb,
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GLuint count, const GLint x[], const GLint y[],
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const GLubyte stencil[])
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{
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const GLint w = rb->Width, h = rb->Height;
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gl_pack_ubyte_stencil_func pack_stencil =
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_mesa_get_pack_ubyte_stencil_func(rb->Format);
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GLuint i;
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for (i = 0; i < count; i++) {
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if (x[i] >= 0 && y[i] >= 0 && x[i] < w && y[i] < h) {
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GLubyte *dst = _swrast_pixel_address(rb, x[i], y[i]);
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pack_stencil(&stencil[i], dst);
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}
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}
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}
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/**
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* /return GL_TRUE = one or more fragments passed,
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* GL_FALSE = all fragments failed.
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*/
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GLboolean
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_swrast_stencil_and_ztest_span(struct gl_context *ctx, SWspan *span)
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{
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struct gl_framebuffer *fb = ctx->DrawBuffer;
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struct gl_renderbuffer *rb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
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const GLint stencilOffset = get_stencil_offset(rb->Format);
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const GLint stencilStride = _mesa_get_format_bytes(rb->Format);
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const GLuint count = span->end;
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GLubyte *mask = span->array->mask;
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GLubyte stencilTemp[MAX_WIDTH];
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GLubyte *stencilBuf;
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if (span->arrayMask & SPAN_XY) {
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/* read stencil values from random locations */
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get_s8_values(ctx, rb, count, span->array->x, span->array->y,
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stencilTemp);
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stencilBuf = stencilTemp;
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}
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else {
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/* Processing a horizontal run of pixels. Since stencil is always
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* 8 bits for all MESA_FORMATs, we just need to use the right offset
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* and stride to access them.
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*/
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stencilBuf = _swrast_pixel_address(rb, span->x, span->y) + stencilOffset;
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}
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/*
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* Apply the stencil test to the fragments.
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* failMask[i] is 1 if the stencil test failed.
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*/
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if (!do_stencil_test(ctx, count, stencilBuf, mask, stencilStride)) {
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/* all fragments failed the stencil test, we're done. */
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span->writeAll = GL_FALSE;
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if (span->arrayMask & SPAN_XY) {
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/* need to write the updated stencil values back to the buffer */
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put_s8_values(ctx, rb, count, span->array->x, span->array->y,
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stencilTemp);
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}
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return GL_FALSE;
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}
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/*
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* Some fragments passed the stencil test, apply depth test to them
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* and apply Zpass and Zfail stencil ops.
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*/
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if (ctx->Depth.Test == GL_FALSE ||
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ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer == NULL) {
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/*
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* No depth buffer, just apply zpass stencil function to active pixels.
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*/
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apply_stencil_op(ctx, ctx->Stencil.ZPassFunc, count,
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stencilBuf, mask, stencilStride);
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}
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else {
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/*
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* Perform depth buffering, then apply zpass or zfail stencil function.
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*/
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GLubyte passMask[MAX_WIDTH], failMask[MAX_WIDTH], origMask[MAX_WIDTH];
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/* save the current mask bits */
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memcpy(origMask, mask, count * sizeof(GLubyte));
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/* apply the depth test */
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_swrast_depth_test_span(ctx, span);
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compute_pass_fail_masks(count, origMask, mask, passMask, failMask);
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/* apply the pass and fail operations */
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if (ctx->Stencil.ZFailFunc != GL_KEEP) {
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apply_stencil_op(ctx, ctx->Stencil.ZFailFunc,
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count, stencilBuf, failMask, stencilStride);
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}
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if (ctx->Stencil.ZPassFunc != GL_KEEP) {
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apply_stencil_op(ctx, ctx->Stencil.ZPassFunc,
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count, stencilBuf, passMask, stencilStride);
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}
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}
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/* Write updated stencil values back into hardware stencil buffer */
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if (span->arrayMask & SPAN_XY) {
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put_s8_values(ctx, rb, count, span->array->x, span->array->y,
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stencilBuf);
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}
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span->writeAll = GL_FALSE;
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return GL_TRUE; /* one or more fragments passed both tests */
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}
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/**
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* Return a span of stencil values from the stencil buffer.
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* Used for glRead/CopyPixels
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* Input: n - how many pixels
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* x,y - location of first pixel
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* Output: stencil - the array of stencil values
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*/
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void
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_swrast_read_stencil_span(struct gl_context *ctx, struct gl_renderbuffer *rb,
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GLint n, GLint x, GLint y, GLubyte stencil[])
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{
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GLubyte *src;
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if (y < 0 || y >= (GLint) rb->Height ||
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x + n <= 0 || x >= (GLint) rb->Width) {
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/* span is completely outside framebuffer */
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return; /* undefined values OK */
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}
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if (x < 0) {
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GLint dx = -x;
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x = 0;
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n -= dx;
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stencil += dx;
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}
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if (x + n > (GLint) rb->Width) {
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GLint dx = x + n - rb->Width;
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n -= dx;
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}
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if (n <= 0) {
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return;
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}
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src = _swrast_pixel_address(rb, x, y);
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_mesa_unpack_ubyte_stencil_row(rb->Format, n, src, stencil);
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}
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/**
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* Write a span of stencil values to the stencil buffer. This function
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* applies the stencil write mask when needed.
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* Used for glDraw/CopyPixels
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* Input: n - how many pixels
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* x, y - location of first pixel
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* stencil - the array of stencil values
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*/
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void
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_swrast_write_stencil_span(struct gl_context *ctx, GLint n, GLint x, GLint y,
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const GLubyte stencil[] )
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{
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struct gl_framebuffer *fb = ctx->DrawBuffer;
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struct gl_renderbuffer *rb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
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const GLuint stencilMax = (1 << fb->Visual.stencilBits) - 1;
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const GLuint stencilMask = ctx->Stencil.WriteMask;
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GLubyte *stencilBuf;
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if (y < 0 || y >= (GLint) rb->Height ||
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x + n <= 0 || x >= (GLint) rb->Width) {
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/* span is completely outside framebuffer */
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return; /* undefined values OK */
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}
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if (x < 0) {
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GLint dx = -x;
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x = 0;
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n -= dx;
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stencil += dx;
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}
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if (x + n > (GLint) rb->Width) {
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GLint dx = x + n - rb->Width;
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n -= dx;
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}
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if (n <= 0) {
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return;
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}
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stencilBuf = _swrast_pixel_address(rb, x, y);
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if ((stencilMask & stencilMax) != stencilMax) {
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/* need to apply writemask */
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GLubyte destVals[MAX_WIDTH], newVals[MAX_WIDTH];
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GLint i;
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_mesa_unpack_ubyte_stencil_row(rb->Format, n, stencilBuf, destVals);
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for (i = 0; i < n; i++) {
|
|
newVals[i]
|
|
= (stencil[i] & stencilMask) | (destVals[i] & ~stencilMask);
|
|
}
|
|
_mesa_pack_ubyte_stencil_row(rb->Format, n, newVals, stencilBuf);
|
|
}
|
|
else {
|
|
_mesa_pack_ubyte_stencil_row(rb->Format, n, stencil, stencilBuf);
|
|
}
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
* Clear the stencil buffer. If the buffer is a combined
|
|
* depth+stencil buffer, only the stencil bits will be touched.
|
|
*/
|
|
void
|
|
_swrast_clear_stencil_buffer(struct gl_context *ctx)
|
|
{
|
|
struct gl_renderbuffer *rb =
|
|
ctx->DrawBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
|
|
const GLubyte stencilBits = ctx->DrawBuffer->Visual.stencilBits;
|
|
const GLuint writeMask = ctx->Stencil.WriteMask;
|
|
const GLuint stencilMax = (1 << stencilBits) - 1;
|
|
GLint x, y, width, height;
|
|
GLubyte *map;
|
|
GLint rowStride, i, j;
|
|
GLbitfield mapMode;
|
|
|
|
if (!rb || writeMask == 0)
|
|
return;
|
|
|
|
/* compute region to clear */
|
|
x = ctx->DrawBuffer->_Xmin;
|
|
y = ctx->DrawBuffer->_Ymin;
|
|
width = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;
|
|
height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
|
|
|
|
mapMode = GL_MAP_WRITE_BIT;
|
|
if ((writeMask & stencilMax) != stencilMax) {
|
|
/* need to mask stencil values */
|
|
mapMode |= GL_MAP_READ_BIT;
|
|
}
|
|
else if (_mesa_get_format_bits(rb->Format, GL_DEPTH_BITS) > 0) {
|
|
/* combined depth+stencil, need to mask Z values */
|
|
mapMode |= GL_MAP_READ_BIT;
|
|
}
|
|
|
|
ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height,
|
|
mapMode, &map, &rowStride);
|
|
if (!map) {
|
|
_mesa_error(ctx, GL_OUT_OF_MEMORY, "glClear(stencil)");
|
|
return;
|
|
}
|
|
|
|
switch (rb->Format) {
|
|
case MESA_FORMAT_S8:
|
|
{
|
|
GLubyte clear = ctx->Stencil.Clear & writeMask & 0xff;
|
|
GLubyte mask = (~writeMask) & 0xff;
|
|
if (mask != 0) {
|
|
/* masked clear */
|
|
for (i = 0; i < height; i++) {
|
|
GLubyte *row = map;
|
|
for (j = 0; j < width; j++) {
|
|
row[j] = (row[j] & mask) | clear;
|
|
}
|
|
map += rowStride;
|
|
}
|
|
}
|
|
else if (rowStride == width) {
|
|
/* clear whole buffer */
|
|
memset(map, clear, width * height);
|
|
}
|
|
else {
|
|
/* clear scissored */
|
|
for (i = 0; i < height; i++) {
|
|
memset(map, clear, width);
|
|
map += rowStride;
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
default:
|
|
_mesa_problem(ctx, "Unexpected stencil buffer format %s"
|
|
" in _swrast_clear_stencil_buffer()",
|
|
_mesa_get_format_name(rb->Format));
|
|
}
|
|
|
|
ctx->Driver.UnmapRenderbuffer(ctx, rb);
|
|
}
|