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/**
* "Mandelbrot" shader demo. Uses the example shaders from
* chapter 15 (or 18) of the OpenGL Shading Language "orange" book.
* 15 Jan 2007
*/
#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glew.h>
#include <GL/gl.h>
#include <GL/glut.h>
#include <GL/glext.h>
#include "extfuncs.h"
#include "shaderutil.h"
static char *FragProgFile = "CH18-mandel.frag";
static char *VertProgFile = "CH18-mandel.vert";
/* program/shader objects */
static GLuint fragShader;
static GLuint vertShader;
static GLuint program;
static struct uniform_info Uniforms[] = {
/* vert */
{ "LightPosition", 3, GL_FLOAT, { 0.1, 0.1, 9.0, 0}, -1 },
{ "SpecularContribution", 1, GL_FLOAT, { 0.5, 0, 0, 0 }, -1 },
{ "DiffuseContribution", 1, GL_FLOAT, { 0.5, 0, 0, 0 }, -1 },
{ "Shininess", 1, GL_FLOAT, { 20.0, 0, 0, 0 }, -1 },
/* frag */
{ "MaxIterations", 1, GL_FLOAT, { 12, 0, 0, 0 }, -1 },
{ "Zoom", 1, GL_FLOAT, { 0.125, 0, 0, 0 }, -1 },
{ "Xcenter", 1, GL_FLOAT, { -1.5, 0, 0, 0 }, -1 },
{ "Ycenter", 1, GL_FLOAT, { .005, 0, 0, 0 }, -1 },
{ "InnerColor", 3, GL_FLOAT, { 1, 0, 0, 0 }, -1 },
{ "OuterColor1", 3, GL_FLOAT, { 0, 1, 0, 0 }, -1 },
{ "OuterColor2", 3, GL_FLOAT, { 0, 0, 1, 0 }, -1 },
END_OF_UNIFORMS
};
static GLint win = 0;
static GLfloat xRot = 0.0f, yRot = 0.0f, zRot = 0.0f;
static GLint uZoom, uXcenter, uYcenter;
static GLfloat zoom = 1.0, xCenter = -1.5, yCenter = 0.0;
static void
Redisplay(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
/* set interactive uniform parameters */
glUniform1fv_func(uZoom, 1, &zoom);
glUniform1fv_func(uXcenter, 1, &xCenter);
glUniform1fv_func(uYcenter, 1, &yCenter);
glPushMatrix();
glRotatef(xRot, 1.0f, 0.0f, 0.0f);
glRotatef(yRot, 0.0f, 1.0f, 0.0f);
glRotatef(zRot, 0.0f, 0.0f, 1.0f);
glBegin(GL_POLYGON);
glTexCoord2f(0, 0); glVertex2f(-1, -1);
glTexCoord2f(1, 0); glVertex2f( 1, -1);
glTexCoord2f(1, 1); glVertex2f( 1, 1);
glTexCoord2f(0, 1); glVertex2f(-1, 1);
glEnd();
glPopMatrix();
glutSwapBuffers();
}
static void
Reshape(int width, int height)
{
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.0f, 0.0f, -6.0f);
}
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 'z':
zoom *= 0.9;
break;
case 'Z':
zoom /= 0.9;
break;
case 27:
CleanUp();
exit(0);
break;
}
glutPostRedisplay();
}
static void
SpecialKey(int key, int x, int y)
{
const GLfloat step = 0.1 * zoom;
(void) x;
(void) y;
switch(key) {
case GLUT_KEY_UP:
yCenter += step;
break;
case GLUT_KEY_DOWN:
yCenter -= step;
break;
case GLUT_KEY_LEFT:
xCenter -= step;
break;
case GLUT_KEY_RIGHT:
xCenter += step;
break;
}
glutPostRedisplay();
}
static void
Init(void)
{
if (!ShadersSupported())
exit(1);
GetExtensionFuncs();
vertShader = CompileShaderFile(GL_VERTEX_SHADER, VertProgFile);
fragShader = CompileShaderFile(GL_FRAGMENT_SHADER, FragProgFile);
program = LinkShaders(vertShader, fragShader);
glUseProgram_func(program);
InitUniforms(program, Uniforms);
uZoom = glGetUniformLocation_func(program, "Zoom");
uXcenter = glGetUniformLocation_func(program, "Xcenter");
uYcenter = glGetUniformLocation_func(program, "Ycenter");
assert(glGetError() == 0);
glClearColor(0.4f, 0.4f, 0.8f, 0.0f);
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(400, 400);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
win = glutCreateWindow(argv[0]);
glewInit();
glutReshapeFunc(Reshape);
glutKeyboardFunc(Key);
glutSpecialFunc(SpecialKey);
glutDisplayFunc(Redisplay);
ParseOptions(argc, argv);
Init();
glutMainLoop();
return 0;
}
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