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authorBrian <[email protected]>2008-04-09 22:27:36 -0600
committerBrian <[email protected]>2008-04-09 22:30:42 -0600
commit90caba3d766406db32e51387f830ce55836f0709 (patch)
treeaeda8950247a00f3b6d307481492a3a48a00880c
parentf9c8af31c5a46d176c732f71259a460753276ef6 (diff)
shader utility functions
-rw-r--r--progs/util/shaderutil.c159
-rw-r--r--progs/util/shaderutil.h34
2 files changed, 193 insertions, 0 deletions
diff --git a/progs/util/shaderutil.c b/progs/util/shaderutil.c
new file mode 100644
index 00000000000..477209ab45f
--- /dev/null
+++ b/progs/util/shaderutil.c
@@ -0,0 +1,159 @@
+/**
+ * Utilities for OpenGL shading language
+ *
+ * Brian Paul
+ * 9 April 2008
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <GL/glut.h>
+#include "extfuncs.h"
+#include "shaderutil.h"
+
+
+static void
+Init(void)
+{
+ static GLboolean firstCall = GL_TRUE;
+ if (firstCall) {
+ GetExtensionFuncs();
+ firstCall = GL_FALSE;
+ }
+}
+
+
+GLboolean
+ShadersSupported(void)
+{
+ const char *version;
+
+ version = (const char *) glGetString(GL_VERSION);
+ if (version[0] != '2' || version[1] != '.') {
+ printf("GL_RENDERER = %s\n",(const char *) glGetString(GL_RENDERER));
+ return GL_FALSE;
+ }
+ return GL_TRUE;
+}
+
+
+GLuint
+CompileShaderText(GLenum shaderType, const char *text)
+{
+ GLuint shader;
+ GLint stat;
+
+ Init();
+
+ shader = glCreateShader_func(shaderType);
+ 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, "Error: problem compiling shader: %s\n", log);
+ exit(1);
+ }
+ else {
+ /*printf("Shader compiled OK\n");*/
+ }
+ return shader;
+}
+
+
+/**
+ * Read a shader from a file.
+ */
+GLuint
+CompileShaderFile(GLenum shaderType, const char *filename)
+{
+ const int max = 100*1000;
+ int n;
+ char *buffer = (char*) malloc(max);
+ GLuint shader;
+
+ FILE *f = fopen(filename, "r");
+ if (!f) {
+ return 0;
+ }
+
+ n = fread(buffer, 1, max, f);
+ /*printf("read %d bytes from shader file %s\n", n, filename);*/
+ if (n > 0) {
+ buffer[n] = 0;
+ shader = CompileShaderText(shaderType, buffer);
+ }
+ else {
+ return 0;
+ }
+
+ fclose(f);
+ free(buffer);
+
+ return shader;
+}
+
+
+GLuint
+LinkShaders(GLuint vertShader, GLuint fragShader)
+{
+ GLuint program = glCreateProgram_func();
+
+ glAttachShader_func(program, fragShader);
+ glAttachShader_func(program, vertShader);
+ glLinkProgram_func(program);
+
+ /* check link */
+ {
+ GLint stat;
+ glGetProgramiv_func(program, GL_LINK_STATUS, &stat);
+ if (!stat) {
+ GLchar log[1000];
+ GLsizei len;
+ glGetProgramInfoLog_func(program, 1000, &len, log);
+ fprintf(stderr, "Shader link error:\n%s\n", log);
+ return 0;
+ }
+ }
+
+ return program;
+}
+
+
+void
+InitUniforms(GLuint program, struct uniform_info uniforms[])
+{
+ GLuint i;
+
+ 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:
+ if (uniforms[i].type == GL_INT)
+ glUniform1i_func(uniforms[i].location,
+ (GLint) uniforms[i].value[0]);
+ else
+ 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();
+ }
+ }
+}
diff --git a/progs/util/shaderutil.h b/progs/util/shaderutil.h
new file mode 100644
index 00000000000..cfb8c1f3b06
--- /dev/null
+++ b/progs/util/shaderutil.h
@@ -0,0 +1,34 @@
+#ifndef SHADER_UTIL_H
+#define SHADER_UTIL_H
+
+
+
+struct uniform_info
+{
+ const char *name;
+ GLuint size;
+ GLenum type; /**< GL_FLOAT or GL_INT */
+ GLfloat value[4];
+ GLint location; /**< filled in by InitUniforms() */
+};
+
+#define END_OF_UNIFORMS { NULL, 0, GL_NONE, { 0, 0, 0, 0 }, -1 }
+
+
+extern GLboolean
+ShadersSupported(void);
+
+extern GLuint
+CompileShaderText(GLenum shaderType, const char *text);
+
+extern GLuint
+CompileShaderFile(GLenum shaderType, const char *filename);
+
+extern GLuint
+LinkShaders(GLuint vertShader, GLuint fragShader);
+
+extern void
+InitUniforms(GLuint program, struct uniform_info uniforms[]);
+
+
+#endif /* SHADER_UTIL_H */