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/**************************************************************************
*
* Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
* 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, sub license, 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 (including the
* next paragraph) 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 NON-INFRINGEMENT.
* IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS 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.
*
**************************************************************************/
/**
* Texture sampling
*
* Authors:
* Brian Paul
*/
#include "main/macros.h"
#include "sp_surface.h"
#include "sp_surface.h"
#include "sp_tex_sample.h"
#include "pipe/p_context.h"
#include "pipe/p_defines.h"
#include "pipe/tgsi/core/tgsi_exec.h"
#define LERP(T, A, B) ( (A) + (T) * ((B) - (A)) )
/**
* Do 2D/biliner interpolation of float values.
* v00, v10, v01 and v11 are typically four texture samples in a square/box.
* a and b are the horizontal and vertical interpolants.
* It's important that this function is inlined when compiled with
* optimization! If we find that's not true on some systems, convert
* to a macro.
*/
static INLINE GLfloat
lerp_2d(GLfloat a, GLfloat b,
GLfloat v00, GLfloat v10, GLfloat v01, GLfloat v11)
{
const GLfloat temp0 = LERP(a, v00, v10);
const GLfloat temp1 = LERP(a, v01, v11);
return LERP(b, temp0, temp1);
}
/**
* Apply texture coord wrapping mode and return integer texture
* row/column/img index.
*/
static INLINE void
nearest_texcoord(GLuint wrapMode, GLfloat s, GLuint width, GLint *k)
{
/* XXX this arithmetic isn't exactly right, add more wrap modes */
switch (wrapMode) {
case PIPE_TEX_WRAP_REPEAT:
*k = (int) (s * width) % width;
break;
case PIPE_TEX_WRAP_CLAMP:
*k = (int) CLAMP(s, 0.0, 1.0) * width;
break;
default:
assert(0);
*k = 0;
}
}
static INLINE void
linear_texcoord(GLuint wrapMode, GLfloat s, GLuint width, GLint *k0, GLint *k1,
GLfloat *a)
{
/* XXX this arithmetic isn't exactly right, add more wrap modes */
switch (wrapMode) {
case PIPE_TEX_WRAP_REPEAT:
*k0 = (int) (s * width) % width;
*k1 = (*k0 + 1) % width;
break;
case PIPE_TEX_WRAP_CLAMP:
*k0 = (int) CLAMP(s, 0.0, 1.0) * width;
*k1 = (*k0 + 1);
if (*k1 >= width)
*k1 = width - 1;
break;
default:
assert(0);
*k0 = *k1 = 0;
}
/* kludge the lerp weight: */
*a = (s * width) - (int) (s * width);
}
/**
* Called via tgsi_sampler::get_sample()
* Use the sampler's state setting to get a filtered RGBA value
* from the sampler's texture (mipmap tree).
*
* XXX we can implement many versions of this function, each
* tightly coded for a specific combination of sampler state
* (nearest + repeat), (bilinear mipmap + clamp), etc.
*
* The update_samplers() function in st_atom_sampler.c could create
* a new tgsi_sampler object for each state combo it finds....
*/
void
sp_get_sample(struct tgsi_sampler *sampler,
const GLfloat strq[4], GLfloat rgba[4])
{
struct pipe_context *pipe = (struct pipe_context *) sampler->pipe;
struct pipe_surface *ps
= pipe->get_tex_surface(pipe, sampler->texture, 0, 0, 0);
switch (sampler->state->min_filter) {
case PIPE_TEX_FILTER_NEAREST:
{
GLint x, y;
nearest_texcoord(sampler->state->wrap_s, strq[0],
sampler->texture->width0, &x);
nearest_texcoord(sampler->state->wrap_t, strq[1],
sampler->texture->height0, &y);
ps->get_tile(ps, x, y, 1, 1, rgba);
}
break;
case PIPE_TEX_FILTER_LINEAR:
{
GLfloat t00[4], t01[4], t10[4], t11[4];
GLint x0, y0, x1, y1;
GLfloat a, b;
linear_texcoord(sampler->state->wrap_s, strq[0],
sampler->texture->width0, &x0, &x1, &a);
linear_texcoord(sampler->state->wrap_t, strq[1],
sampler->texture->height0, &y0, &y1, &b);
ps->get_tile(ps, x0, y0, 1, 1, t00);
ps->get_tile(ps, x1, y0, 1, 1, t10);
ps->get_tile(ps, x0, y1, 1, 1, t01);
ps->get_tile(ps, x1, y1, 1, 1, t11);
rgba[0] = lerp_2d(a, b, t00[0], t10[0], t01[0], t11[0]);
rgba[1] = lerp_2d(a, b, t00[1], t10[1], t01[1], t11[1]);
rgba[2] = lerp_2d(a, b, t00[2], t10[2], t01[2], t11[2]);
rgba[3] = lerp_2d(a, b, t00[3], t10[3], t01[3], t11[3]);
}
break;
default:
assert(0);
}
}
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