shader3/GPUProgram.cpp

#include "GPUProgram.h"
#include "utils.h"
#include <stdio.h>

GLuint CompileShader(const char*shaderPath, GLenum shaderType)
{
	GLuint shader = glCreateShader(shaderType);
	const char* code = LoadFileContent(shaderPath);
	if (code == nullptr)
	{
		printf("cannot load shader source from file %s\n", shaderPath);
		return 0;
	}
	glShaderSource(shader, 1, &code, nullptr);//ram -> vram
	glCompileShader(shader);
	GLint nResult;
	glGetShaderiv(shader, GL_COMPILE_STATUS, &nResult);
	if (nResult == GL_FALSE)
	{
		printf("compile shader %s fail\n", shaderPath);
		GLint logLength;
		glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &logLength);
		char*log = new char[logLength];
		GLsizei writed = 0;
		glGetShaderInfoLog(shader, logLength, &writed, log);
		printf("%s\n", log);
		delete log;
		glDeleteShader(shader);
		return 0;
	}
	return shader;
}


GPUProgram::GPUProgram()
{
	mProgram = glCreateProgram();
}

GPUProgram::~GPUProgram()
{

}

void GPUProgram::AttachShader(GLenum shaderType, const char*shaderPath)
{
	GLuint shader = CompileShader(shaderPath, shaderType);
	if (shader!=0)
	{
		glAttachShader(mProgram, shader);
		mAttachedShaders.push(shader);
	}
}

void GPUProgram::Link()
{
	glLinkProgram(mProgram);
	GLint nResult;
	glGetProgramiv(mProgram, GL_LINK_STATUS, &nResult);
	if (nResult == GL_FALSE)
	{
		printf("create gpu program fail,link error\n");
		GLint logLength;
		glGetProgramiv(mProgram, GL_INFO_LOG_LENGTH, &logLength);
		char*log = new char[logLength];
		GLsizei writed = 0;
		glGetProgramInfoLog(mProgram, logLength, &writed, log);
		printf("%s\n", log);
		delete log;
		glDeleteProgram(mProgram);
		mProgram = 0;
	}
	while (!mAttachedShaders.empty())
	{
		GLuint shader = mAttachedShaders.top();
		glDetachShader(mProgram, shader);
		glDeleteShader(shader);
		mAttachedShaders.pop();
	}
}

void GPUProgram::DetectAttribute(const char*attributeName)
{
	GLint loc = glGetAttribLocation(mProgram, attributeName);
	if (loc!=-1)
	{
		mLocations.insert(std::pair<std::string,GLint>(attributeName,loc));
	}
}

void GPUProgram::DetectUniform(const char*uniformName)
{
	GLint loc = glGetUniformLocation(mProgram, uniformName);
	if (loc != -1)
	{
		mLocations.insert(std::pair<std::string, GLint>(uniformName, loc));
	}
}

GLint GPUProgram::GetLocation(const char*name)
{
	auto iter = mLocations.find(name);
	if (iter ==mLocations.end())
	{
		return -1;
	}
	return iter->second;
}