shader.c

#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <stdio.h>
#include <GL/gl3w.h>
#include "shader.h"
int loadShader( unsigned int shader, const char * path ) {
	// First, let's get the filesize
	struct stat s;
	stat(path, &s);
	int shader_length = s.st_size;
	
	// Open the file in read-only mode
	FILE * shaderfile;
	shaderfile = fopen(path, "rb");
	
	// Allocate required mem
	char * shadercode;
	shadercode = malloc(shader_length + 1); // + extra byte for \0
	shadercode[shader_length] = '\0';

	// Read the data
	fread(shadercode, sizeof(char), shader_length, shaderfile);
	
	// Tell OpenGL what the source is
	glShaderSource(shader, 1, (const char **)&shadercode, &shader_length);
	
	// Clean up after ourselves!
	free(shadercode);
	fclose(shaderfile);
	
	return 0;
};

void compileShader( unsigned int shader ) {
	int errorLength = 0;
	int success;
	glCompileShader(shader);
	glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
	if( !success ) {
		glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &errorLength);
		if( errorLength > 1 ) {
			char* errorMessage = malloc(errorLength);
			glGetShaderInfoLog(shader, errorLength, NULL, errorMessage);
			fprintf(stderr, "%s\n", errorMessage);
			free(errorMessage);
		}
	}
}

int buildShader( unsigned int vs, unsigned int fs, unsigned int po ) {
	compileShader(vs);
	compileShader(fs);
	
	glAttachShader(po, vs);
	glAttachShader(po, fs);
	
	glLinkProgram(po);
	
	return checkProgForErrors(po);
};

int checkProgForErrors( unsigned int prog ) {
	int errorLength = 0;
	glGetProgramiv(prog, GL_INFO_LOG_LENGTH, &errorLength);
	if(errorLength > 1) { // 0 characters of length + \0 = 1 character of length
		char* errorMessage;
		errorMessage = malloc(errorLength);
		glGetProgramInfoLog(prog, errorLength, NULL, errorMessage);
		fprintf(stderr, "%s\n", errorMessage);
		free(errorMessage);
		return 1;
	}
	return 0;
}