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initShader.cpp
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initShader.cpp
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//#include "Angel.h"
#include "include/Angel.h"
#include <stdio.h>
#include <stdlib.h>
namespace Angel
{
// Create a NULL-terminated string by reading the provided file
static char*
readShaderSource(const char* shaderFile)
{
FILE* fp = fopen(shaderFile, "r");
if (fp == NULL) {
return NULL;
}
fseek(fp, 0L, SEEK_END);
long size = ftell(fp);
fseek(fp, 0L, SEEK_SET);
char* buf = new char[size + 1];
fread(buf, 1, size, fp);
buf[size] = '\0';
fclose(fp);
return buf;
}
// Create a GLSL program object from vertex and fragment shader files
GLuint
InitShader(const char* vShaderFile, const char* fShaderFile)
{
struct Shader {
const char* filename;
GLenum type;
GLchar* source;
} shaders[2] = {
{ vShaderFile, GL_VERTEX_SHADER, NULL },
{ fShaderFile, GL_FRAGMENT_SHADER, NULL }
};
GLuint program = glCreateProgram();
for (int i = 0; i < 2; ++i) {
Shader& s = shaders[i];
s.source = readShaderSource(s.filename);
if (shaders[i].source == NULL) {
std::cerr << "Failed to read " << s.filename << std::endl;
exit(EXIT_FAILURE);
}
GLuint shader = glCreateShader(s.type);
glShaderSource(shader, 1, (const GLchar**) &s.source, NULL);
glCompileShader(shader);
GLint compiled;
glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
if (!compiled) {
std::cerr << s.filename << " failed to compile:" << std::endl;
GLint logSize;
glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &logSize);
char* logMsg = new char[logSize];
glGetShaderInfoLog(shader, logSize, NULL, logMsg);
std::cerr << logMsg << std::endl;
delete [] logMsg;
exit(EXIT_FAILURE);
}
delete [] s.source;
glAttachShader(program, shader);
}
/* link and error check */
glLinkProgram(program);
GLint linked;
glGetProgramiv(program, GL_LINK_STATUS, &linked);
if (!linked) {
std::cerr << "Shader program failed to link" << std::endl;
GLint logSize;
glGetProgramiv(program, GL_INFO_LOG_LENGTH, &logSize);
char* logMsg = new char[logSize];
glGetProgramInfoLog(program, logSize, NULL, logMsg);
std::cerr << logMsg << std::endl;
delete [] logMsg;
exit(EXIT_FAILURE);
}
/* use program object */
glUseProgram(program);
return program;
}
} // Close namespace Angel block