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/*
* Copyright (c) 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.
*/
/**
* @file fbo-fragcoord2.c
*
* Test GLSL gl_FragCoord, gl_Frontfacing, polygon CCW vs CW and culling
* with an FBO
*
* Author: Brian Paul
*/
#include "piglit-util-gl-common.h"
#include "piglit-framework.h"
PIGLIT_GL_TEST_MAIN(
256 /*window_width*/,
256 /*window_height*/,
GLUT_RGB | GLUT_DOUBLE)
static GLuint prog;
static const char *TestName = "fbo-fragcoord2";
static GLuint FBO;
static char *VertShaderText =
"void main() \n"
"{ \n"
" gl_Position = ftransform(); \n"
"} \n";
static char *FragShaderText =
"void main() \n"
"{ \n"
" vec4 scale = vec4(1.0/255.0, 1.0/255.0, 1.0, 1.0); \n"
" if (gl_FrontFacing) { \n"
" // front-facing \n"
" gl_FragColor = gl_FragCoord * scale; \n"
" gl_FragColor.z = 0.0; \n"
" } else { \n"
" // back-facing \n"
" gl_FragColor = vec4(0, 0, 1, 1); \n"
" } \n"
"} \n";
static void
check_error(int line)
{
GLenum err = glGetError();
if (err) {
printf("%s: Unexpected error 0x%x at line %d\n",
TestName, err, line);
piglit_report_result(PIGLIT_FAIL);
}
}
static void
create_fbo(void)
{
GLuint rb;
glGenFramebuffersEXT(1, &FBO);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, FBO);
glGenRenderbuffersEXT(1, &rb);
check_error(__LINE__);
glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, rb);
check_error(__LINE__);
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT,
GL_COLOR_ATTACHMENT0,
GL_RENDERBUFFER_EXT,
rb);
check_error(__LINE__);
glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_RGBA,
piglit_width, piglit_height);
check_error(__LINE__);
}
static void
rect(float x0, float y0, float x1, float y1)
{
glBegin(GL_POLYGON);
glVertex2f(x0, y0);
glVertex2f(x1, y0);
glVertex2f(x1, y1);
glVertex2f(x0, y1);
glEnd();
}
static enum piglit_result
test(void)
{
static const GLfloat black[4] = {0, 0, 0, 1};
static const GLfloat blue[4] = {0, 0, 1, 1};
static const GLfloat half_red[4] = {0.5, 0, 0, 1};
static const GLfloat half_green[4] = {0, 0.5, 0, 1};
static const GLfloat green_half_red[4] = {0.5, 1, 0, 1};
GLenum buffer;
enum piglit_result result = PIGLIT_PASS;
create_fbo();
/* draw to fbo */
buffer = GL_COLOR_ATTACHMENT0_EXT;
glDrawBuffersARB(1, &buffer);
glReadBuffer(buffer);
/* test drawing */
glClearColor(0, 0, 0, 0);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(prog);
glEnable(GL_CULL_FACE);
/* left half: front-facing, color varies with fragcoord */
glFrontFace(GL_CCW);
glCullFace(GL_BACK);
rect(0, 0, piglit_width / 2, piglit_height);
/* right half: back-facing, blue */
glFrontFace(GL_CW);
glCullFace(GL_FRONT);
rect(piglit_width/2, 0, piglit_width, piglit_height);
glUseProgram(0);
glDisable(GL_CULL_FACE);
/* copy image from FBO to window */
{
GLubyte *buf;
buf = malloc(piglit_width * piglit_height * 4);
glReadPixels(0, 0, piglit_width, piglit_height, GL_RGBA, GL_UNSIGNED_BYTE, buf);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
glDrawBuffer(GL_BACK);
glClear(GL_COLOR_BUFFER_BIT);
glDrawPixels(piglit_width, piglit_height, GL_RGBA, GL_UNSIGNED_BYTE, buf);
free(buf);
}
/* left half probes */
if (!piglit_probe_pixel_rgb(0, 0, black)) {
result = PIGLIT_FAIL;
}
if (!piglit_probe_pixel_rgb(piglit_width/2-1, 0, half_red)) {
result = PIGLIT_FAIL;
}
if (!piglit_probe_pixel_rgb(0, piglit_height/2, half_green)) {
result = PIGLIT_FAIL;
}
if (!piglit_probe_pixel_rgb(piglit_width/2-1, piglit_height-1, green_half_red)) {
result = PIGLIT_FAIL;
}
/* right half probe */
if (!piglit_probe_pixel_rgb(piglit_width*3/4, piglit_height/2, blue)) {
result = PIGLIT_FAIL;
}
glutSwapBuffers();
return result;
}
enum piglit_result
piglit_display(void)
{
return test();
}
void
piglit_init(int argc, char**argv)
{
GLuint vs, fs;
if (piglit_get_gl_version() < 20) {
printf("Requires OpenGL 2.0\n");
piglit_report_result(PIGLIT_SKIP);
}
piglit_require_extension("GL_ARB_framebuffer_object");
piglit_ortho_projection(piglit_width, piglit_height, GL_FALSE);
vs = piglit_compile_shader_text(GL_VERTEX_SHADER, VertShaderText);
assert(vs);
fs = piglit_compile_shader_text(GL_FRAGMENT_SHADER, FragShaderText);
assert(fs);
prog = piglit_link_simple_program(vs, fs);
assert(prog);
}
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