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Check for overflow when converting floating pt Z values to 32-bit GLuint.

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This commit is contained in:
Brian Paul 2006-05-06 22:30:33 +00:00
parent efbf170cfb
commit 0c7cbf0a7c
1 changed files with 39 additions and 8 deletions
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47
src/mesa/swrast/s_copypix.c
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@ -1,8 +1,8 @@
/*
* Mesa 3-D graphics library
* Version: 6.5
* Version: 6.5.1
*
* Copyright (C) 1999-2005 Brian Paul All Rights Reserved.
* Copyright (C) 1999-2006 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"),
@ -478,6 +478,41 @@ copy_ci_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
}
/**
* Convert floating point Z values to integer Z values with pixel transfer's
* Z scale and bias.
*/
static void
scale_and_bias_z(GLcontext *ctx, GLuint width,
const GLfloat depth[], GLuint z[])
{
const GLuint depthMax = ctx->DrawBuffer->_DepthMax;
GLuint i;
if (depthMax <= 0xffffff &&
ctx->Pixel.DepthScale == 1.0 &&
ctx->Pixel.DepthBias == 0.0) {
/* no scale or bias and no clamping and no worry of overflow */
const GLfloat depthMaxF = ctx->DrawBuffer->_DepthMaxF;
for (i = 0; i < width; i++) {
z[i] = (GLuint) (depth[i] * depthMaxF);
}
}
else {
/* need to be careful with overflow */
const GLdouble depthMaxF = ctx->DrawBuffer->_DepthMaxF;
for (i = 0; i < width; i++) {
GLdouble d = depth[i] * ctx->Pixel.DepthScale + ctx->Pixel.DepthBias;
d = CLAMP(d, 0.0, 1.0) * depthMaxF;
if (d >= depthMaxF)
z[i] = depthMax;
else
z[i] = (GLuint) d;
}
}
}
/*
* TODO: Optimize!!!!
@ -490,10 +525,9 @@ copy_depth_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
SWcontext *swrast = SWRAST_CONTEXT(ctx);
struct gl_framebuffer *fb = ctx->ReadBuffer;
struct gl_renderbuffer *readRb = fb->_DepthBuffer;
const GLfloat depthMax = fb->_DepthMaxF;
GLfloat *p, *tmpImage;
GLint sy, dy, stepy;
GLint i, j;
GLint j;
const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
GLint overlapping;
struct sw_span span;
@ -562,10 +596,7 @@ copy_depth_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
}
/* apply scale and bias */
for (i = 0; i < width; i++) {
GLfloat d = depth[i] * ctx->Pixel.DepthScale + ctx->Pixel.DepthBias;
span.array->z[i] = (GLuint) (CLAMP(d, 0.0F, 1.0F) * depthMax);
}
scale_and_bias_z(ctx, width, depth, span.array->z);
/* write depth values */
span.x = destx;