Added new directory of GL shading language demos: glsl
diff --git a/progs/glsl/mandelbrot.c b/progs/glsl/mandelbrot.c
new file mode 100644
index 0000000..a6c326b
--- /dev/null
+++ b/progs/glsl/mandelbrot.c
@@ -0,0 +1,317 @@
+/**
+ * "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/gl.h>
+#include <GL/glut.h>
+#include <GL/glext.h>
+#include "extfuncs.h"
+
+
+static char *FragProgFile = "CH18-mandel.frag.txt";
+static char *VertProgFile = "CH18-mandel.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} },
+ { "SpecularContribution", 1, -1, { 0.5, 0, 0, 0 } },
+ { "DiffuseContribution", 1, -1, { 0.5, 0, 0, 0 } },
+ { "Shininess", 1, -1, { 20.0, 0, 0, 0 } },
+ /* frag */
+ { "MaxIterations", 1, -1, { 12, 0, 0, 0 } },
+ { "Zoom", 1, -1, { 0.5, 0, 0, 0 } },
+ { "Xcenter", 1, -1, { -1.0, 0, 0, 0 } },
+ { "Ycenter", 1, -1, { .005, 0, 0, 0 } },
+ { "InnerColor", 3, -1, { 1, 0, 0, 0 } },
+ { "OuterColor1", 3, -1, { 0, 1, 0, 0 } },
+ { "OuterColor2", 3, -1, { 0, 0, 1, 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(-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':
+ 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;
+}
+