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meta: Convert Z value from normalized to object-space in meta code 

Convert Z from a normalized value in the range [0, 1] to an
object-space Z coordinate in [-1, +1] so that drawing at the new Z
position with the default/identity ortho projection results in the
original Z value.  Used by the meta-Clear, Draw/CopyPixels and Bitmap
functions where the Z value comes from the clear value or raster
position.

Fixes piglit tests fdo23670-depth_test, quad-invariance and
glsl-orangebook-ch06-bump as well as oglc zbfunc.c.

https://bugs.freedesktop.org/show_bug.cgi?id=23670
This commit is contained in:
Brian Paul 2010-05-24 17:21:30 -04:00 committed by Kristian Høgsberg
parent e88cef3c9d
commit a949558430
1 changed files with 19 additions and 4 deletions
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23
src/mesa/drivers/common/meta.c
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@ -817,6 +817,21 @@ _mesa_meta_end(GLcontext *ctx)
}
/**
* Convert Z from a normalized value in the range [0, 1] to an object-space
* Z coordinate in [-1, +1] so that drawing at the new Z position with the
* default/identity ortho projection results in the original Z value.
* Used by the meta-Clear, Draw/CopyPixels and Bitmap functions where the Z
* value comes from the clear value or raster position.
*/
static INLINE GLfloat
invert_z(GLfloat normZ)
{
GLfloat objZ = 1.0 - 2.0 * normZ;
return objZ;
}
/**
* One-time init for a temp_texture object.
* Choose tex target, compute max tex size, etc.
@ -1438,7 +1453,7 @@ _mesa_meta_Clear(GLcontext *ctx, GLbitfield buffers)
const GLfloat y0 = (GLfloat) ctx->DrawBuffer->_Ymin;
const GLfloat x1 = (GLfloat) ctx->DrawBuffer->_Xmax;
const GLfloat y1 = (GLfloat) ctx->DrawBuffer->_Ymax;
const GLfloat z = 1.0 - 2.0 * ctx->Depth.Clear;
const GLfloat z = invert_z(ctx->Depth.Clear);
GLuint i;
verts[0].x = x0;
@ -1544,7 +1559,7 @@ _mesa_meta_CopyPixels(GLcontext *ctx, GLint srcX, GLint srcY,
const GLfloat dstY0 = (GLfloat) dstY;
const GLfloat dstX1 = dstX + width * ctx->Pixel.ZoomX;
const GLfloat dstY1 = dstY + height * ctx->Pixel.ZoomY;
const GLfloat z = ctx->Current.RasterPos[2];
const GLfloat z = invert_z(ctx->Current.RasterPos[2]);
verts[0].x = dstX0;
verts[0].y = dstY0;
@ -1833,7 +1848,7 @@ _mesa_meta_DrawPixels(GLcontext *ctx,
const GLfloat y0 = (GLfloat) y;
const GLfloat x1 = x + width * ctx->Pixel.ZoomX;
const GLfloat y1 = y + height * ctx->Pixel.ZoomY;
const GLfloat z = ctx->Current.RasterPos[2];
const GLfloat z = invert_z(ctx->Current.RasterPos[2]);
verts[0].x = x0;
verts[0].y = y0;
@ -2036,7 +2051,7 @@ _mesa_meta_Bitmap(GLcontext *ctx,
const GLfloat y0 = (GLfloat) y;
const GLfloat x1 = (GLfloat) (x + width);
const GLfloat y1 = (GLfloat) (y + height);
const GLfloat z = ctx->Current.RasterPos[2];
const GLfloat z = invert_z(ctx->Current.RasterPos[2]);
GLuint i;
verts[0].x = x0;