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Diffstat (limited to 'progs/glsl/brick.c')
| -rw-r--r-- | progs/glsl/brick.c | 311 |
1 files changed, 311 insertions, 0 deletions
diff --git a/progs/glsl/brick.c b/progs/glsl/brick.c new file mode 100644 index 00000000000..522698b5d43 --- /dev/null +++ b/progs/glsl/brick.c @@ -0,0 +1,311 @@ +/** + * "Brick" shader demo. Uses the example shaders from chapter 6 of + * the OpenGL Shading Language "orange" book. + * 10 Jan 2007 + */ + +#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" + + +static char *FragProgFile = "CH06-brick.frag.txt"; +static char *VertProgFile = "CH06-brick.vert.txt"; + +/* program/shader objects */ +static GLuint fragShader; +static GLuint vertShader; +static GLuint program; + + +struct uniform_info { + const char *name; + GLuint size; + GLint location; + GLfloat value[4]; +}; + +static struct uniform_info Uniforms[] = { + /* vert */ + { "LightPosition", 3, -1, { 0.1, 0.1, 9.0, 0} }, + /* frag */ + { "BrickColor", 3, -1, { 0.8, 0.2, 0.2, 0 } }, + { "MortarColor", 3, -1, { 0.6, 0.6, 0.6, 0 } }, + { "BrickSize", 2, -1, { 1.0, 0.3, 0, 0 } }, + { "BrickPct", 2, -1, { 0.9, 0.8, 0, 0 } }, + { NULL, 0, 0, { 0, 0, 0, 0 } } +}; + +static GLint win = 0; + + +static GLfloat xRot = 0.0f, yRot = 0.0f, zRot = 0.0f; + + + + +static void +Redisplay(void) +{ + glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); + + 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(-2, -2); + glTexCoord2f(1, 0); glVertex2f( 2, -2); + glTexCoord2f(1, 1); glVertex2f( 2, 2); + glTexCoord2f(0, 1); glVertex2f(-2, 2); + 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, -15.0f); +} + + +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': + zRot -= 1.0; + break; + case 'Z': + zRot += 1.0; + 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 +LoadAndCompileShader(GLuint shader, const char *text) +{ + GLint stat; + + glShaderSource_func(shader, 1, (const GLchar **) &text, NULL); + + glCompileShader_func(shader); + + glGetShaderiv_func(shader, GL_COMPILE_STATUS, &stat); + if (!stat) { + GLchar log[1000]; + GLsizei len; + glGetShaderInfoLog_func(shader, 1000, &len, log); + fprintf(stderr, "brick: problem compiling shader: %s\n", log); + exit(1); + } + else { + printf("Shader compiled OK\n"); + } +} + + +/** + * Read a shader from a file. + */ +static void +ReadShader(GLuint shader, const char *filename) +{ + const int max = 100*1000; + int n; + char *buffer = (char*) malloc(max); + FILE *f = fopen(filename, "r"); + if (!f) { + fprintf(stderr, "brick: Unable to open shader file %s\n", filename); + exit(1); + } + + n = fread(buffer, 1, max, f); + printf("brick: read %d bytes from shader file %s\n", n, filename); + if (n > 0) { + buffer[n] = 0; + LoadAndCompileShader(shader, buffer); + } + + fclose(f); + free(buffer); +} + + +static void +CheckLink(GLuint prog) +{ + GLint stat; + glGetProgramiv_func(prog, GL_LINK_STATUS, &stat); + if (!stat) { + GLchar log[1000]; + GLsizei len; + glGetProgramInfoLog_func(prog, 1000, &len, log); + fprintf(stderr, "Linker error:\n%s\n", log); + } + else { + fprintf(stderr, "Link success!\n"); + } +} + + +static void +Init(void) +{ + const char *version; + GLint i; + + version = (const char *) glGetString(GL_VERSION); + if (version[0] != '2' || version[1] != '.') { + printf("Warning: this program expects OpenGL 2.0\n"); + /*exit(1);*/ + } + + GetExtensionFuncs(); + + vertShader = glCreateShader_func(GL_VERTEX_SHADER); + ReadShader(vertShader, VertProgFile); + + fragShader = glCreateShader_func(GL_FRAGMENT_SHADER); + ReadShader(fragShader, FragProgFile); + + program = glCreateProgram_func(); + glAttachShader_func(program, fragShader); + glAttachShader_func(program, vertShader); + glLinkProgram_func(program); + CheckLink(program); + glUseProgram_func(program); + + for (i = 0; Uniforms[i].name; i++) { + Uniforms[i].location + = glGetUniformLocation_func(program, Uniforms[i].name); + printf("Uniform %s location: %d\n", Uniforms[i].name, + Uniforms[i].location); + switch (Uniforms[i].size) { + case 1: + glUniform1fv_func(Uniforms[i].location, 1, Uniforms[i].value); + break; + case 2: + glUniform2fv_func(Uniforms[i].location, 1, Uniforms[i].value); + break; + case 3: + glUniform3fv_func(Uniforms[i].location, 1, Uniforms[i].value); + break; + case 4: + glUniform4fv_func(Uniforms[i].location, 1, Uniforms[i].value); + break; + default: + abort(); + } + } + + 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]); + glutReshapeFunc(Reshape); + glutKeyboardFunc(Key); + glutSpecialFunc(SpecialKey); + glutDisplayFunc(Redisplay); + ParseOptions(argc, argv); + Init(); + glutMainLoop(); + return 0; +} + |