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/**
* Test very basic glsl functionality (identity vertex and fragment shaders).
* Brian Paul & Stephane Marchesin
*/
#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/gl.h>
#include <GL/glut.h>
#include <GL/glext.h>
#include "extfuncs.h"
#include "shaderutil.h"
static char *FragProgFile = NULL;
static char *VertProgFile = NULL;
static GLuint fragShader;
static GLuint vertShader;
static GLuint program;
static GLint win = 0;
static GLboolean anim = GL_FALSE;
static GLfloat xRot = 0.0f, yRot = 0.0f;
static int w,h;
static void
Redisplay(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glBegin(GL_TRIANGLES);
glColor3f(.8,0,0);
glVertex3f(-0.9, -0.9, 0.0);
glColor3f(0,.9,0);
glVertex3f( 0.9, -0.9, 0.0);
glColor3f(0,0,.7);
glVertex3f( 0.0, 0.9, 0.0);
glEnd();
glutSwapBuffers();
}
static void
Idle(void)
{
yRot = glutGet(GLUT_ELAPSED_TIME) * 0.1;
glutPostRedisplay();
}
static void
Reshape(int width, int height)
{
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
w = width;
h = height;
}
static void
CleanUp(void)
{
glDeleteShader_func(fragShader);
glDeleteShader_func(vertShader);
glDeleteProgram_func(program);
glutDestroyWindow(win);
}
static void
Key(unsigned char key, int x, int y)
{
(void) x;
(void) y;
switch(key) {
case ' ':
case 'a':
anim = !anim;
if (anim)
glutIdleFunc(Idle);
else
glutIdleFunc(NULL);
break;
case 27:
CleanUp();
exit(0);
break;
}
glutPostRedisplay();
}
static void
SpecialKey(int key, int x, int y)
{
const GLfloat step = 3.0f;
(void) x;
(void) y;
switch(key) {
case GLUT_KEY_UP:
xRot -= step;
break;
case GLUT_KEY_DOWN:
xRot += step;
break;
case GLUT_KEY_LEFT:
yRot -= step;
break;
case GLUT_KEY_RIGHT:
yRot += step;
break;
}
glutPostRedisplay();
}
static void
Init(void)
{
static const char *fragShaderText =
"void main() {\n"
" gl_FragColor = vec4(1.0,0.0,0.0,1.0);\n"
"}\n";
static const char *vertShaderText =
"void main() {\n"
" gl_Position = gl_Vertex;\n"
"}\n";
if (!ShadersSupported())
exit(1);
GetExtensionFuncs();
if (FragProgFile)
fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, FragProgFile);
else
fragShader = CompileShaderText(GL_FRAGMENT_SHADER, fragShaderText);
if (VertProgFile)
vertShader = CompileShaderFile(GL_VERTEX_SHADER, VertProgFile);
else
vertShader = CompileShaderText(GL_VERTEX_SHADER, vertShaderText);
program = LinkShaders(vertShader, fragShader);
glUseProgram_func(program);
/*assert(glGetError() == 0);*/
glClearColor(0.3f, 0.3f, 0.3f, 0.0f);
glEnable(GL_DEPTH_TEST);
printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
assert(glIsProgram_func(program));
assert(glIsShader_func(fragShader));
assert(glIsShader_func(vertShader));
glColor3f(1, 0, 0);
}
static void
ParseOptions(int argc, char *argv[])
{
int i;
for (i = 1; i < argc; i++) {
if (strcmp(argv[i], "-fs") == 0) {
FragProgFile = argv[i+1];
}
else if (strcmp(argv[i], "-vs") == 0) {
VertProgFile = argv[i+1];
}
}
}
int
main(int argc, char *argv[])
{
glutInit(&argc, argv);
glutInitWindowPosition( 0, 0);
glutInitWindowSize(200, 200);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
win = glutCreateWindow(argv[0]);
glutReshapeFunc(Reshape);
glutKeyboardFunc(Key);
glutSpecialFunc(SpecialKey);
glutDisplayFunc(Redisplay);
if (anim)
glutIdleFunc(Idle);
ParseOptions(argc, argv);
Init();
glutMainLoop();
return 0;
}
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