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/*
* Copyright © 2009 Intel Corporation
* Copyright © 2011 VMware, Inc.
*
* 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 (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 NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS 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.
*
* Authors:
* Eric Anholt <eric@anholt.net>
* Brian Paul
*
*/
/** @file glsl-fs-fragcoord-zw-perspective.c
*
* Tests that gl_FragCoord.zw produces the expected output in a fragment shader
* with a perspective projection.
*/
#include "piglit-util-gl.h"
PIGLIT_GL_TEST_CONFIG_BEGIN
config.supports_gl_compat_version = 10;
config.window_width = 256;
config.window_height = 256;
config.window_visual = PIGLIT_GL_VISUAL_RGB | PIGLIT_GL_VISUAL_DOUBLE | PIGLIT_GL_VISUAL_DEPTH;
config.khr_no_error_support = PIGLIT_NO_ERRORS;
PIGLIT_GL_TEST_CONFIG_END
static GLfloat Znear = 1.0, Zfar = 10.0;
/**
* Draw a quad where the bottom edge is on the near clip plane and the
* top edge is on the far clip plane. Adjust the far coordinates' X and Y
* values to fill the window. So the quad doesn't look like it's drawn in
* perspective, but it is (the top is much wider than the bottom).
*/
static void
draw_quad(void)
{
float xBotLeft = -Znear, xBotRight = Znear;
float xTopLeft = -Zfar, xTopRight = Zfar;
float yBotLeft = -Znear, yBotRight = -Znear;
float yTopLeft = Zfar, yTopRight = Zfar;
float zBottom = -Znear, zTop = -Zfar;
float verts[4][4];
verts[0][0] = xBotLeft;
verts[0][1] = yBotLeft;
verts[0][2] = zBottom;
verts[0][3] = 1.0;
verts[1][0] = xBotRight;
verts[1][1] = yBotRight;
verts[1][2] = zBottom;
verts[1][3] = 1.0;
verts[2][0] = xTopRight;
verts[2][1] = yTopRight;
verts[2][2] = zTop;
verts[2][3] = 1.0;
verts[3][0] = xTopLeft;
verts[3][1] = yTopLeft;
verts[3][2] = zTop;
verts[3][3] = 1.0;
glVertexPointer(4, GL_FLOAT, 0, verts);
glEnableClientState(GL_VERTEX_ARRAY);
glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
glDisableClientState(GL_VERTEX_ARRAY);
}
/** Convert t in [0,1] into a 1/w value */
static float
t_to_w(float t)
{
float zEye = -(Znear + t * (Zfar - Znear));
float wClip = -zEye;
return 1.0 / wClip;
}
enum piglit_result
piglit_display(void)
{
float w0, w1;
GLboolean pass = GL_TRUE;
int y;
glClearColor(0.5, 0.5, 0.5, 0.5);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
draw_quad();
/* Spot-test Z values */
pass = piglit_probe_pixel_depth(0, 0, 0.0) && pass;
pass = piglit_probe_pixel_depth(piglit_width-1, 0, 0.0) && pass;
pass = piglit_probe_pixel_depth(piglit_width-2, piglit_height-1, 1.0) && pass;
pass = piglit_probe_pixel_depth(1, piglit_height-2, 1.0) && pass;
w0 = t_to_w(0.0);
w1 = t_to_w(1.0);
/* Test a column of pixel colors */
for (y = 8; y < piglit_height; y += 16) {
float expected[3];
float t = y / (float) (piglit_height - 1);
expected[0] = t; /* gl_FragCoord.z */
expected[1] = w0 + t * (w1 - w0); /* gl_FragCoord.w */
expected[2] = 0.0;
pass = piglit_probe_pixel_rgb(piglit_width/2, y, expected) & pass;
}
piglit_present_results();
return pass ? PIGLIT_PASS : PIGLIT_FAIL;
}
void
piglit_init(int argc, char **argv)
{
GLint vs, fs, prog;
piglit_require_gl_version(20);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-1.0, 1.0, -1.0, 1.0, Znear, Zfar);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
vs = piglit_compile_shader(GL_VERTEX_SHADER,
"shaders/glsl-mvp.vert");
fs = piglit_compile_shader(GL_FRAGMENT_SHADER,
"shaders/glsl-fs-fragcoord-zw.frag");
prog = piglit_link_simple_program(vs, fs);
glUseProgram(prog);
glEnable(GL_DEPTH_TEST);
}
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