1 files changed, 102 insertions, 0 deletions
diff --git a/src/shader.c b/src/shader.c
new file mode 100644
index 0000000..e21277f
--- /dev/null
+++ b/src/shader.c
@@ -0,0 +1,102 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <GL/glew.h>
+#include "shader.h"
+
+static char *getShaderSource(const char *shaderPath);
+static void checkShaderCompile(unsigned int shader, const char *shaderPath);
+static void checkProgramLink(unsigned int shader);
+
+char
+*getShaderSource(const char *shaderPath)
+{
+    long fileSize;
+    char *shaderSource;
+    FILE *shaderFile = fopen(shaderPath, "r");
+
+    if (!shaderFile) {
+        perror("getShaderSource() ERROR");
+        exit(1);
+    }
+
+    fseek(shaderFile, 0L, SEEK_END);
+    fileSize = ftell(shaderFile);
+    if (!fileSize) {
+        fprintf(stderr, "getShaderSource() ERROR: %s file is empty\n", shaderPath);
+        exit(1);
+    }
+
+    rewind(shaderFile);
+
+    shaderSource = malloc(fileSize * sizeof(char));
+    if (!fscanf(shaderFile, "%[^\\]", shaderSource)) {
+        perror("getShaderSource() ERROR");
+        exit(1);
+    }
+
+    fclose(shaderFile);
+    return shaderSource;
+}
+
+void
+checkShaderCompile(unsigned int shader, const char *shaderPath)
+{
+    int success;
+    char infoLog[512];
+
+    glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
+    if (!success) {
+        glGetShaderInfoLog(shader, 512, NULL, infoLog);
+        fprintf(stderr, "shaderCompile() ERROR\n%s %s\n", shaderPath, infoLog);
+        exit(1);
+    }
+}
+
+void
+checkProgramLink(unsigned int shaderProgram)
+{
+    int success;
+    char infoLog[512];
+    glLinkProgram(shaderProgram);
+    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
+    if (!success) {
+        glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
+        fprintf(stderr, "shaderProgramLink() ERROR\n%s\n", infoLog);
+        exit(1);
+    }
+}
+
+unsigned int
+shaderCreateProgram(const char *vertexShaderPath, const char *fragmentShaderPath)
+{
+    unsigned int vertexShader, fragmentShader, shaderProgram;
+    char *vertexShaderSource, *fragmentShaderSource;
+
+    vertexShader = glCreateShader(GL_VERTEX_SHADER);
+    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+
+    vertexShaderSource = getShaderSource(vertexShaderPath);
+    fragmentShaderSource = getShaderSource(fragmentShaderPath);
+
+    glShaderSource(vertexShader, 1, (const char **)&vertexShaderSource, NULL);
+    glCompileShader(vertexShader);
+    checkShaderCompile(vertexShader, vertexShaderPath);
+
+    glShaderSource(fragmentShader, 1, (const char **)&fragmentShaderSource, NULL);
+    glCompileShader(fragmentShader);
+    checkShaderCompile(fragmentShader, fragmentShaderPath);
+
+    shaderProgram = glCreateProgram();
+    glAttachShader(shaderProgram, vertexShader);
+    glAttachShader(shaderProgram, fragmentShader);
+    glLinkProgram(shaderProgram);
+    checkProgramLink(shaderProgram);
+
+    glDeleteShader(vertexShader);
+    glDeleteShader(fragmentShader);
+    free(vertexShaderSource);
+    free(fragmentShaderSource);
+
+    return shaderProgram;
+}