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llvmpipe: fix sprite texcoord setup for non-projective texturing

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Normally the Mesa state tracker uses TXP instructions for texturing.
But if a fragment shader uses texture2D() that's a TEX instruction.
In that case we were incorrectly computing the texcoord coefficients
in the point sprite setup code.  Some new comments in the code explain
things.
This commit is contained in:
Brian Paul 2010-09-22 11:20:48 -06:00
parent bd6b8107ad
commit 516ac2bd50
1 changed files with 58 additions and 27 deletions
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85
src/gallium/drivers/llvmpipe/lp_setup_point.c
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@ -65,47 +65,77 @@ constant_coef(struct lp_setup_context *setup,
}
/**
* Setup automatic texcoord coefficients (for sprite rendering).
* \param slot the vertex attribute slot to setup
* \param i the attribute channel in [0,3]
* \param sprite_coord_origin one of PIPE_SPRITE_COORD_x
* \param perspective_proj will the TEX instruction do a divide by Q?
*/
static void
perspective_coef(struct lp_setup_context *setup,
struct lp_rast_triangle *point,
const struct point_info *info,
unsigned slot,
unsigned vert_attr,
unsigned i,
unsigned sprite_coord_origin)
texcoord_coef(struct lp_setup_context *setup,
struct lp_rast_triangle *point,
const struct point_info *info,
unsigned slot,
unsigned i,
unsigned sprite_coord_origin,
boolean perspective_proj)
{
assert(i < 4);
if (i == 0) {
float dadx = FIXED_ONE / (float)info->dx12;
float dady = 0.0f;
point->inputs.dadx[slot][i] = dadx;
point->inputs.dady[slot][i] = dady;
point->inputs.a0[slot][i] = (0.5 -
(dadx * ((float)info->v0[0][0] - setup->pixel_offset) +
dady * ((float)info->v0[0][1] - setup->pixel_offset)));
float x0 = info->v0[0][0] - setup->pixel_offset;
float y0 = info->v0[0][1] - setup->pixel_offset;
point->inputs.dadx[slot][0] = dadx;
point->inputs.dady[slot][0] = dady;
point->inputs.a0[slot][0] = 0.5 - (dadx * x0 + dady * y0);
if (!perspective_proj) {
/* Divide coefficients by vertex.w here.
*
* It would be clearer to always multiply by w0 above and
* then divide it out for perspective projection here, but
* doing it this way involves less algebra.
*/
float w0 = info->v0[0][3];
point->inputs.dadx[slot][0] *= w0;
point->inputs.dady[slot][0] *= w0;
point->inputs.a0[slot][0] *= w0;
}
}
else if (i == 1) {
float dadx = 0.0f;
float dady = FIXED_ONE / (float)info->dx12;
float x0 = info->v0[0][0] - setup->pixel_offset;
float y0 = info->v0[0][1] - setup->pixel_offset;
if (sprite_coord_origin == PIPE_SPRITE_COORD_LOWER_LEFT) {
dady = -dady;
}
point->inputs.dadx[slot][i] = dadx;
point->inputs.dady[slot][i] = dady;
point->inputs.a0[slot][i] = (0.5 -
(dadx * ((float)info->v0[0][0] - setup->pixel_offset) +
dady * ((float)info->v0[0][1] - setup->pixel_offset)));
point->inputs.dadx[slot][1] = dadx;
point->inputs.dady[slot][1] = dady;
point->inputs.a0[slot][1] = 0.5 - (dadx * x0 + dady * y0);
if (!perspective_proj) {
float w0 = info->v0[0][3];
point->inputs.dadx[slot][1] *= w0;
point->inputs.dady[slot][1] *= w0;
point->inputs.a0[slot][1] *= w0;
}
}
else if (i == 2) {
point->inputs.a0[slot][i] = 0.0f;
point->inputs.dadx[slot][i] = 0.0f;
point->inputs.dady[slot][i] = 0.0f;
point->inputs.a0[slot][2] = 0.0f;
point->inputs.dadx[slot][2] = 0.0f;
point->inputs.dady[slot][2] = 0.0f;
}
else if (i == 3) {
point->inputs.a0[slot][i] = 1.0f;
point->inputs.dadx[slot][i] = 0.0f;
point->inputs.dady[slot][i] = 0.0f;
else {
point->inputs.a0[slot][3] = 1.0f;
point->inputs.dadx[slot][3] = 0.0f;
point->inputs.dady[slot][3] = 0.0f;
}
}
@ -184,7 +214,7 @@ setup_point_coefficients( struct lp_setup_context *setup,
case LP_INTERP_PERSPECTIVE:
/* check if the sprite coord flag is set for this attribute.
* If so, set it up so it up so x any y vary from 0 to 1.
* If so, set it up so it up so x and y vary from 0 to 1.
*/
if (shader->info.input_semantic_name[slot] == TGSI_SEMANTIC_GENERIC) {
const int index = shader->info.input_semantic_index[slot];
@ -195,8 +225,9 @@ setup_point_coefficients( struct lp_setup_context *setup,
(setup->sprite_coord_enable & (1 << index))) {
for (i = 0; i < NUM_CHANNELS; i++)
if (usage_mask & (1 << i))
perspective_coef(setup, point, info, slot+1, vert_attr, i,
setup->sprite_coord_origin);
texcoord_coef(setup, point, info, slot + 1, i,
setup->sprite_coord_origin,
(usage_mask & TGSI_WRITEMASK_W));
fragcoord_usage_mask |= TGSI_WRITEMASK_W;
break;
}