| /* Test fragment shader */ |
| |
| #include <assert.h> |
| #include <string.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <math.h> |
| #include <GL/glew.h> |
| #include <GL/glut.h> |
| |
| |
| static GLuint fragShader; |
| static GLuint vertShader; |
| static GLuint program; |
| static GLint win = 0; |
| static GLfloat xpos = 0, ypos = 0; |
| |
| |
| static void |
| Redisplay(void) |
| { |
| glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); |
| |
| glPushMatrix(); |
| glTranslatef(xpos, ypos, 0); |
| |
| glBegin(GL_TRIANGLES); |
| glColor3f(1, 0, 0); |
| glVertex2f(-0.9, -0.9); |
| glColor3f(0, 1, 0); |
| glVertex2f( 0.9, -0.9); |
| glColor3f(0, 0, 1); |
| glVertex2f( 0, 0.9); |
| glEnd(); |
| |
| glPopMatrix(); |
| |
| glutSwapBuffers(); |
| } |
| |
| |
| static void |
| Reshape(int width, int height) |
| { |
| glViewport(0, 0, width, height); |
| glMatrixMode(GL_PROJECTION); |
| glLoadIdentity(); |
| glOrtho(-1, 1, -1, 1, -1, 1); |
| glMatrixMode(GL_MODELVIEW); |
| glLoadIdentity(); |
| } |
| |
| |
| static void |
| CleanUp(void) |
| { |
| glDeleteShader(fragShader); |
| glDeleteShader(vertShader); |
| glDeleteProgram(program); |
| glutDestroyWindow(win); |
| } |
| |
| |
| static void |
| Key(unsigned char key, int x, int y) |
| { |
| (void) x; |
| (void) y; |
| |
| switch(key) { |
| case 27: |
| CleanUp(); |
| exit(0); |
| break; |
| } |
| glutPostRedisplay(); |
| } |
| |
| |
| static void |
| SpecialKey(int key, int x, int y) |
| { |
| const GLfloat step = 0.1; |
| |
| (void) x; |
| (void) y; |
| |
| switch(key) { |
| case GLUT_KEY_UP: |
| ypos += step; |
| break; |
| case GLUT_KEY_DOWN: |
| ypos -= step; |
| break; |
| case GLUT_KEY_LEFT: |
| xpos -= step; |
| break; |
| case GLUT_KEY_RIGHT: |
| xpos += step; |
| break; |
| } |
| glutPostRedisplay(); |
| } |
| |
| |
| static void |
| LoadAndCompileShader(GLuint shader, const char *text) |
| { |
| GLint stat; |
| |
| glShaderSource(shader, 1, (const GLchar **) &text, NULL); |
| |
| glCompileShader(shader); |
| |
| glGetShaderiv(shader, GL_COMPILE_STATUS, &stat); |
| if (!stat) { |
| GLchar log[1000]; |
| GLsizei len; |
| glGetShaderInfoLog(shader, 1000, &len, log); |
| fprintf(stderr, "fslight: problem compiling shader:\n%s\n", log); |
| exit(1); |
| } |
| } |
| |
| |
| static void |
| CheckLink(GLuint prog) |
| { |
| GLint stat; |
| glGetProgramiv(prog, GL_LINK_STATUS, &stat); |
| if (!stat) { |
| GLchar log[1000]; |
| GLsizei len; |
| glGetProgramInfoLog(prog, 1000, &len, log); |
| fprintf(stderr, "Linker error:\n%s\n", log); |
| } |
| } |
| |
| |
| static void |
| Init(void) |
| { |
| /* fragment color is a function of fragment position: */ |
| static const char *fragShaderText = |
| "void main() {\n" |
| " gl_FragColor = gl_FragCoord * vec4(0.005); \n" |
| " //gl_FragColor = gl_Color; \n" |
| " //gl_FragColor = vec4(1, 0, 0.5, 0); \n" |
| "}\n"; |
| #if 0 |
| static const char *vertShaderText = |
| "varying vec3 normal;\n" |
| "void main() {\n" |
| " gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n" |
| " normal = gl_NormalMatrix * gl_Normal;\n" |
| "}\n"; |
| #endif |
| const char *version; |
| |
| version = (const char *) glGetString(GL_VERSION); |
| if (version[0] != '2' || version[1] != '.') { |
| printf("This program requires OpenGL 2.x, found %s\n", version); |
| exit(1); |
| } |
| |
| fragShader = glCreateShader(GL_FRAGMENT_SHADER); |
| LoadAndCompileShader(fragShader, fragShaderText); |
| |
| #if 0 |
| vertShader = glCreateShader(GL_VERTEX_SHADER); |
| LoadAndCompileShader(vertShader, vertShaderText); |
| #endif |
| |
| program = glCreateProgram(); |
| glAttachShader(program, fragShader); |
| #if 0 |
| glAttachShader(program, vertShader); |
| #endif |
| glLinkProgram(program); |
| CheckLink(program); |
| glUseProgram(program); |
| |
| assert(glGetError() == 0); |
| |
| glClearColor(0.3f, 0.3f, 0.3f, 0.0f); |
| |
| printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER)); |
| } |
| |
| |
| 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]); |
| glewInit(); |
| glutReshapeFunc(Reshape); |
| glutKeyboardFunc(Key); |
| glutSpecialFunc(SpecialKey); |
| glutDisplayFunc(Redisplay); |
| Init(); |
| glutMainLoop(); |
| return 0; |
| } |
| |
| |