wip

1 files changed, 63 insertions, 0 deletions

diff --git a/src/shader.c b/src/shader.c
new file mode 100644
index 0000000..c78a7e5
--- /dev/null
+++ b/src/shader.c
@@ -0,0 +1,63 @@
+#include "shader.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+
+
+/**
+ * Simple method to read shaders from path and return a string
+ * containing the code. Function allocates memory which needs 
+ * to be cleaned up
+ * @param path Path to shader GLSL file
+ * @return buf Contents of shader file as a string
+ */
+char* read_shader(char* path) {
+    FILE* file = fopen(path, "r");
+    fseek(file, 0, SEEK_END);
+    int file_size = ftell(file);
+    rewind(file);
+    char* buf = malloc(file_size);
+    fread(buf, file_size, 1, file);
+    return buf;
+}
+
+/**
+ * Compile some given shader code
+ * @param type The type of shader (GL_VERTEX_SHADER, GL_FRAGMENT_SHADER etc)
+ * @param code The string corresponding to the shader code
+ * @return shader The GLuint pointer to the compiled shader
+ */
+GLuint compile_shader(GLuint type, const char* code) {
+    GLuint shader = glCreateShader(type);
+    glShaderSource(shader, 1, &code, NULL);
+    glCompileShader(shader);
+    return shader;
+}
+
+/*
+ * Given a vertex and fragment shader, link and compile a shader program,
+ * returning the GLuint pointing to that program
+ * @param vs The vertex shader string, usually returend from read_shader
+ * @param fs The fragment shader string, usually returend from read_shader
+ * @return shader_program The pointer to the compiled shader
+ */
+GLuint create_shader_program(const char* vs, const char* fs) {
+    GLuint shader_program = glCreateProgram();
+    GLuint vertex_shader = compile_shader(GL_VERTEX_SHADER, vs);
+    GLuint fragment_shader = compile_shader(GL_FRAGMENT_SHADER, fs);
+    glAttachShader(shader_program, fragment_shader);
+    glAttachShader(shader_program, vertex_shader);
+    glLinkProgram(shader_program);
+    return shader_program;
+}
+
+
+GLuint shader_init() {
+    char* shaders[2] = { "shaders/fragment.glsl", "shaders/vertex.glsl" };
+    char* fragment_shader = read_shader(shaders[0]);
+    char* vertex_shader = read_shader(shaders[1]);
+    GLuint shader_program = create_shader_program(vertex_shader, fragment_shader);
+    free(vertex_shader);
+    free(fragment_shader);
+    return shader_program;
+}