用着色器编写第一个程序

  我们用着色编写画一个三角形

   

#include<Gl/glew.h>
//#include<gl/glxew.h>
#include<Gl/gl.h>
#include<GL/GLU.h>
#include<Gl/glut.h>
#include<stdio.h>
#include<malloc.h>
#include<glm/glm.hpp>
#include<glm/gtc/matrix_transform.hpp>
#include<glm/gtx/transform.hpp>
using  glm::vec3;
using  glm::vec4;
void render()
{
	GLenum err = glewInit();
	if (GLEW_OK != err)
		fprintf(stderr, "error initializaing GLew %s
", glewGetErrorString(err));
	GLuint vertShader = glCreateShader(GL_VERTEX_SHADER);
	const GLchar *codearray[] = {
		"#version 430                      
"
		"in vec3 VertexPosition;        
"
		"in vec3 VertexColor;             
"
		"out vec3 Color ;
"
		" void main()                   
"
		"{                                
"
		"	Color = VertexColor;                  
"
		"	gl_Position = vec4(VertexPosition, 1.0);           
"
		"}              
"

	};
	glShaderSource(vertShader, 1, codearray, NULL);
	glCompileShader(vertShader);
	GLuint fragShader = glCreateShader(GL_FRAGMENT_SHADER);
	const GLchar* codearray_frag[] = {
		"#version    430                         
"
		"in vec3 Color;                         
"
		"out vec4 FragColor;                    
"
		"void  main()                           
"
		"{                                      
"
		"FragColor=vec4(Color,1.0);             
"
		"}                                      
"
	};
	glShaderSource(fragShader, 1, codearray_frag, NULL);
	glCompileShader(fragShader);
	GLuint programHandle = glCreateProgram();
	if (0 == programHandle)
	{
		fprintf(stderr, "error creating program 
");
		exit(0);
	}
	glAttachShader(programHandle, vertShader);
	glAttachShader(programHandle, fragShader);
	glBindAttribLocation(programHandle, 0, "VertexPosition");
	glBindAttribLocation(programHandle, 1, "VertexColor");
	GLuint vaoHandle;
	float positionData[] = {
		-0.8f, -0.8f, 0.0f,
		0.8f, -0.8f, 0.0f,
		0.0f, 0.8f, 0.0f
	};
	float colorData[] = {
		1.0f, 0.0f, 0.0f,
		0.0f, 1.0f, 0.0f,
		0.f, 0.0f, 1.0f
	};
	GLuint vboHandle[2];
	glGenBuffers(2, vboHandle);
	GLuint positionbufferHandle = vboHandle[0];
	GLuint colorBufferHandle = vboHandle[1];
	glBindBuffer(GL_ARRAY_BUFFER, positionbufferHandle);
	glBufferData(GL_ARRAY_BUFFER, 9 * sizeof(float), positionData, GL_STATIC_DRAW);
	glBindBuffer(GL_ARRAY_BUFFER, colorBufferHandle);
	glBufferData(GL_ARRAY_BUFFER, 9 * sizeof(float), colorData, GL_STATIC_DRAW);
	glGenVertexArrays(1, &vaoHandle);
	glBindVertexArray(vaoHandle);
	glEnableVertexAttribArray(0);
	glEnableVertexAttribArray(1);
	glBindBuffer(GL_ARRAY_BUFFER, positionbufferHandle);
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (GLubyte*)NULL);
	glBindBuffer(GL_ARRAY_BUFFER, colorBufferHandle);
	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 0, (GLubyte*)NULL);
	glBindVertexArray(vaoHandle);
	//	glDrawArrays
	glDrawArrays(GL_TRIANGLES, 0, 3);
	glLinkProgram(programHandle);




	GLint result;
	glGetShaderiv(programHandle, GL_COMPILE_STATUS, &result);
	if (GL_FALSE == result)
	{
		fprintf(stderr, "vertex shader compilation failed
");
		GLint loglen;
		glGetProgramiv(programHandle, GL_LINK_STATUS, &loglen);
		if (loglen > 0)
		{
			char*log = (char*)malloc(loglen);
			GLsizei written;
			glGetProgramInfoLog(programHandle, loglen, &written, log);
			fprintf(stderr, "shader log:%s
", log);
			free(log);
		}
	}
	else
	{
		;//	glUseProgram(programHandle);
	}
	glUseProgram(programHandle);
	/*
	const	GLubyte*renderer = glGetString(GL_RENDER);
	const	GLubyte *vendor = glGetString(GL_VENDOR);
	const	GLubyte *version = glGetString(GL_VERSION);
	const	GLubyte *glslVersion = glGetString(GL_SHADING_LANGUAGE_VERSION);
	GLint major, minor;
	glGetIntegerv(GL_MAJOR_VERSION, &major);
	glGetIntegerv(GL_MINOR_VERSION, &minor);
	printf("GL vendor:%s
", vendor);
	printf("GL renderer:%s
", renderer);
	printf("GL version(s):%s
", version);
	printf("GL version(d):%d,%d
", major,minor);
	printf("GL version:%s
", glslVersion);

	*/
	;


}
int main(int argc, char**argv)
{

	glutInit(&argc, argv);

	glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
	glutCreateWindow("ss");
	
	glutDisplayFunc(render);

	glutMainLoop();
	return 0;
	//vec3 VertexPosition = vec3(1, 0,  1.0f);
	//vec3 VertexColor = vec3(1.0f, 0, 0)	;



	//return 0;
}