From 2702c90d7a39fca2a3319c5e915fd290cb31fc70 Mon Sep 17 00:00:00 2001 From: Radosław Kujawa Date: Fri, 17 Jul 2026 14:54:32 +0200 Subject: Initial import. --- src/mesa/swrast/s_alphabuf.c | 332 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 332 insertions(+) create mode 100644 src/mesa/swrast/s_alphabuf.c (limited to 'src/mesa/swrast/s_alphabuf.c') diff --git a/src/mesa/swrast/s_alphabuf.c b/src/mesa/swrast/s_alphabuf.c new file mode 100644 index 0000000..f57449c --- /dev/null +++ b/src/mesa/swrast/s_alphabuf.c @@ -0,0 +1,332 @@ +/* + * Mesa 3-D graphics library + * Version: 6.1 + * + * Copyright (C) 1999-2004 Brian Paul All Rights Reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included + * in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS + * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN + * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + + +/* + * Software alpha planes. Many frame buffers don't have alpha bits so + * we simulate them in software. + */ + + +#include "glheader.h" +#include "colormac.h" +#include "context.h" +#include "imports.h" + +#include "s_context.h" +#include "s_alphabuf.h" + + +/* + * Allocate a new front and back alpha buffer. + */ +void +_swrast_alloc_alpha_buffers( GLframebuffer *buffer ) +{ + const GLint bytes = buffer->Width * buffer->Height * sizeof(GLchan); + + ASSERT(buffer->UseSoftwareAlphaBuffers); + + if (buffer->FrontLeftAlpha) { + MESA_PBUFFER_FREE( buffer->FrontLeftAlpha ); + } + buffer->FrontLeftAlpha = (GLchan *) MESA_PBUFFER_ALLOC( bytes ); + if (!buffer->FrontLeftAlpha) { + /* out of memory */ + _mesa_error( NULL, GL_OUT_OF_MEMORY, + "Couldn't allocate front-left alpha buffer" ); + } + + if (buffer->Visual.doubleBufferMode) { + if (buffer->BackLeftAlpha) { + MESA_PBUFFER_FREE( buffer->BackLeftAlpha ); + } + buffer->BackLeftAlpha = (GLchan *) MESA_PBUFFER_ALLOC( bytes ); + if (!buffer->BackLeftAlpha) { + /* out of memory */ + _mesa_error( NULL, GL_OUT_OF_MEMORY, + "Couldn't allocate back-left alpha buffer" ); + } + } + + if (buffer->Visual.stereoMode) { + if (buffer->FrontRightAlpha) { + MESA_PBUFFER_FREE( buffer->FrontRightAlpha ); + } + buffer->FrontRightAlpha = (GLchan *) MESA_PBUFFER_ALLOC( bytes ); + if (!buffer->FrontRightAlpha) { + /* out of memory */ + _mesa_error( NULL, GL_OUT_OF_MEMORY, + "Couldn't allocate front-right alpha buffer" ); + } + + if (buffer->Visual.doubleBufferMode) { + if (buffer->BackRightAlpha) { + MESA_PBUFFER_FREE( buffer->BackRightAlpha ); + } + buffer->BackRightAlpha = (GLchan *) MESA_PBUFFER_ALLOC( bytes ); + if (!buffer->BackRightAlpha) { + /* out of memory */ + _mesa_error( NULL, GL_OUT_OF_MEMORY, + "Couldn't allocate back-right alpha buffer" ); + } + } + } +} + + +/* + * Clear all the alpha buffers + */ +void +_swrast_clear_alpha_buffers( GLcontext *ctx ) +{ + GLchan aclear; + GLuint bufferBit; + + CLAMPED_FLOAT_TO_CHAN(aclear, ctx->Color.ClearColor[3]); + + ASSERT(ctx->DrawBuffer->UseSoftwareAlphaBuffers); + ASSERT(ctx->Color.ColorMask[ACOMP]); + + /* loop over four possible alpha buffers */ + for (bufferBit = 1; bufferBit <= 8; bufferBit = bufferBit << 1) { + if (bufferBit & ctx->Color._DrawDestMask) { + GLchan *buffer; + if (bufferBit == DD_FRONT_LEFT_BIT) { + buffer = ctx->DrawBuffer->FrontLeftAlpha; + } + else if (bufferBit == DD_FRONT_RIGHT_BIT) { + buffer = ctx->DrawBuffer->FrontRightAlpha; + } + else if (bufferBit == DD_BACK_LEFT_BIT) { + buffer = ctx->DrawBuffer->BackLeftAlpha; + } + else { + buffer = ctx->DrawBuffer->BackRightAlpha; + } + + if (ctx->Scissor.Enabled) { + /* clear scissor region */ + GLint j; + GLint rowLen = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin; + GLint rows = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin; + GLint width = ctx->DrawBuffer->Width; + GLchan *aptr = buffer + + ctx->DrawBuffer->_Ymin * ctx->DrawBuffer->Width + + ctx->DrawBuffer->_Xmin; + for (j = 0; j < rows; j++) { +#if CHAN_BITS == 8 + MEMSET( aptr, aclear, rowLen ); +#elif CHAN_BITS == 16 + MEMSET16( aptr, aclear, rowLen ); +#else + GLint i; + for (i = 0; i < rowLen; i++) { + aptr[i] = aclear; + } +#endif + aptr += width; + } + } + else { + /* clear whole buffer */ + GLuint pixels = ctx->DrawBuffer->Width * ctx->DrawBuffer->Height; +#if CHAN_BITS == 8 + MEMSET(buffer, aclear, pixels); +#elif CHAN_BITS == 16 + MEMSET16(buffer, aclear, pixels); +#else + GLuint i; + for (i = 0; i < pixels; i++) { + buffer[i] = aclear; + } +#endif + } + } + } +} + + + +static INLINE +GLchan *get_alpha_buffer( GLcontext *ctx ) +{ + SWcontext *swrast = SWRAST_CONTEXT(ctx); + + switch (swrast->CurrentBufferBit) { + case DD_FRONT_LEFT_BIT: + return ctx->DrawBuffer->FrontLeftAlpha; + case DD_BACK_LEFT_BIT: + return ctx->DrawBuffer->BackLeftAlpha; + case DD_FRONT_RIGHT_BIT: + return ctx->DrawBuffer->FrontRightAlpha; + case DD_BACK_RIGHT_BIT: + return ctx->DrawBuffer->BackRightAlpha; + default: + _mesa_problem(ctx, "Bad CurrentBuffer in get_alpha_buffer()"); + return (GLchan *) ctx->DrawBuffer->FrontLeftAlpha; + } +} + + +void +_swrast_write_alpha_span( GLcontext *ctx, GLuint n, GLint x, GLint y, + CONST GLchan rgba[][4], const GLubyte mask[] ) +{ + GLchan *buffer, *aptr; + GLuint i; + + buffer = get_alpha_buffer(ctx); + aptr = buffer + y * ctx->DrawBuffer->Width + x; + + if (mask) { + for (i=0;iDrawBuffer->Width + x; + + if (mask) { + for (i=0;iDrawBuffer->Width + x[i]; + *aptr = rgba[i][ACOMP]; + } + } + } + else { + for (i=0;iDrawBuffer->Width + x[i]; + *aptr = rgba[i][ACOMP]; + } + } +} + + +void +_swrast_write_mono_alpha_pixels( GLcontext *ctx, + GLuint n, const GLint x[], const GLint y[], + GLchan alpha, const GLubyte mask[] ) +{ + GLchan *buffer; + GLuint i; + + buffer = get_alpha_buffer(ctx); + + if (mask) { + for (i=0;iDrawBuffer->Width + x[i]; + *aptr = alpha; + } + } + } + else { + for (i=0;iDrawBuffer->Width + x[i]; + *aptr = alpha; + } + } +} + + + +void +_swrast_read_alpha_span( GLcontext *ctx, + GLuint n, GLint x, GLint y, GLchan rgba[][4] ) +{ + const GLchan *buffer, *aptr; + GLuint i; + + buffer = get_alpha_buffer(ctx); + aptr = buffer + y * ctx->DrawBuffer->Width + x; + + for (i = 0; i < n; i++) + rgba[i][ACOMP] = *aptr++; +} + + +void +_swrast_read_alpha_pixels( GLcontext *ctx, + GLuint n, const GLint x[], const GLint y[], + GLchan rgba[][4], const GLubyte mask[] ) +{ + const GLchan *buffer; + GLuint i; + + buffer = get_alpha_buffer(ctx); + + for (i = 0; i < n; i++) { + if (mask[i]) { + const GLchan *aptr = buffer + y[i] * ctx->DrawBuffer->Width + x[i]; + rgba[i][ACOMP] = *aptr; + } + } +} -- cgit