opengl模型加载

opengl模型加载

opengl模型加载，将模型中的顶点和纹理坐标写到buffer中。将buffer数据传过opengl.

#include "glew.h"
#include <glfw3.h>
#include "common/loadShader.h"
#include "common/controls.h"
#include "common/objloader.h"

#include "glm.hpp"
#include "ext.hpp"
GLFWwindow* window;
int main(void)
{
	//GLFWwindow* window;

	/* Initialize the library */
	if (!glfwInit())
		return -1;

	/* Create a windowed mode window and its OpenGL context */
	window = glfwCreateWindow(480, 320, "Hello World", NULL, NULL);
	if (!window)
	{
		glfwTerminate();
		return -1;
	}

	/* Make the window's context current */
	glfwMakeContextCurrent(window);

	// Needed in core profile
	if( glewInit() != GLEW_OK)
	{
		glfwTerminate();
		return -1;
	}

	// Our vertices. Tree consecutive floats give a 3D vertex; Three consecutive vertices give a triangle.
	// A cube has 6 faces with 2 triangles each, so this makes 6*2=12 triangles, and 12*3 vertices
	std::vector<glm::vec3> vertices;
	std::vector<glm::vec2> uvs;
	std::vector<glm::vec3> normals; // Won't be used at the moment.
	bool res = loadOBJ("cube.obj", vertices, uvs, normals);
	
	//This will identify our vertex buffer
	GLuint vertexbuffer;

	
	//Generate 1 buffer,put the resulting identifier in vertexbuffer
	glGenBuffers(1,&vertexbuffer);		

	//The following commands will talk about our 'vertexbuffer' buffer
	glBindBuffer(GL_ARRAY_BUFFER,vertexbuffer);

	//Give our vertices to OpenGL.
 	glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(glm::vec3), &vertices[0], GL_STATIC_DRAW);

	GLuint uvbuffer;
	glGenBuffers(1, &uvbuffer);
	glBindBuffer(GL_ARRAY_BUFFER, uvbuffer);
	glBufferData(GL_ARRAY_BUFFER, uvs.size() * sizeof(glm::vec2), &uvs[0], GL_STATIC_DRAW);

	GLuint Texture = loadBMP_custom("./resource/uvtemplate.bmp");
	// One color for each vertex. They were generated randomly.	


	GLuint programID = LoadShaders("./shader/vertex.shader","./shader/fragment.shader");
	
	glClearColor(0.0f, 0.0f, 0.4f, 0.0f);
	/* Loop until the user closes the window */

	// Projection matrix : 45° Field of View, 4:3 ratio, display range : 0.1 unit  100 units
	//glm::mat4 Projection = glm::ortho(-4.0f/3.0f, 4.0f/3.0f, -1.0f, 1.0f, 0.1f, 100.0f);
	
	
		
	
		// Get a handle for our "MVP" uniform.
		// Only at initialisation time.
		GLuint MatrixID = glGetUniformLocation(programID,"MVP");
	
		// Send our transformation to the currently bound shader,
		// in the "MVP" uniform
		// For each model you render, since the MVP will be different (at least the M part)
		

		GLuint TextureID = glGetUniformLocation(programID,"myTextureSampler");
		int width,height;	
		glfwGetWindowSize(window,&width,&height);
		float centerX = width;
		float centerY = height;
		centerX /= 2;
		centerY /= 2;
		glfwSetCursorPos(window,centerX,centerY);
		
	while (glfwGetKey(window, GLFW_KEY_ESCAPE ) != GLFW_PRESS && !glfwWindowShouldClose(window))
	{
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		glUseProgram(programID);
		computeMatricesFromInputs();
		glm::mat4 Projection = getProjectionMatrix();
		glm::mat4 View = getViewMatrix();
		//Model matrix : an identity matrix (model will be at the origin)
		glm::mat4 Model = glm::mat4(1.0f);

		// Our ModelViewProjection : multiplication of our 3 matrices
		glm::mat4 MVP = Projection * View * Model;// Remember, matrix multiplication is the other way around
		glUniformMatrix4fv(MatrixID,1,GL_FALSE,&MVP[0][0]);


		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D,Texture);
		glUniform1i(TextureID, 0);
		

		glEnableVertexAttribArray(0);
		glBindBuffer(GL_ARRAY_BUFFER,vertexbuffer);
		glVertexAttribPointer(
			0,			// attribute 0. No particular reason for 0, but must match the layout in the shader.
			3,			// size
			GL_FLOAT,	// type
			GL_FALSE,	// normalized?
			0,			// stride
			(void*)0	// array buffer offset
			);

		

		glEnableVertexAttribArray(1);
		glBindBuffer(GL_ARRAY_BUFFER,uvbuffer);	
		glVertexAttribPointer(
			1,			// attribute 0. No particular reason for 0, but must match the layout in the shader.
			2,			// size
			GL_FLOAT,	// type
			GL_FALSE,	// normalized?
			0,			// stride
			(void*)0	// array buffer offset
			);

		glEnable(GL_DEPTH_TEST);
		glDepthFunc(GL_LESS);
		glDrawArrays(GL_TRIANGLES,0,12*3);// Starting from vertex 0; 3 vertices total -> 1 triangle
		
			
		

		
		

		
		glDisableVertexAttribArray(0);
		glDisableVertexAttribArray(1);
		/* Swap front and back buffers */
		glfwSwapBuffers(window);

		/* Poll for and process events */
		glfwPollEvents();
	}

	glfwTerminate();
	return 0;
}

loadobj

#include "stdio.h"
#include "objloader.h"

bool loadOBJ(
	const char* path,
	std::vector<glm::vec3> & out_vertices,
	std::vector<glm::vec2> & out_uvs,
	std::vector<glm::vec3> & out_normals
	)
{
	std::vector<unsigned int> vertexIndices,uvIndices,normalIndices;
	std::vector<glm::vec3> temp_vertices;
	std::vector<glm::vec2> temp_uvs;
	std::vector<glm::vec3> temp_normals;

	FILE * file = fopen(path,"r");
	if (file == NULL)
	{
		printf("IMpossible to open the file !\n");
		return false;
	}

	while(1){
		char lineHeader[128];
		int res = fscanf(file,"%s",lineHeader);
		if (res == EOF)
		{
			break;
		}

		if (strcmp(lineHeader,"v") == 0)
		{
			glm::vec3 vertex;
			fscanf(file,"%f %f %f\n",&vertex.x,&vertex.y,&vertex.z);
			temp_vertices.push_back(vertex);
		}else if (strcmp(lineHeader,"vt") == 0)
		{
			glm::vec2 uv;
			fscanf(file,"%f %f\n",&uv.x,&uv.y);
			uv.y = -uv.y;
			temp_uvs.push_back(uv);
		}
		else if (strcmp(lineHeader,"vn")== 0)
		{
			glm::vec3 normal;
			fscanf(file,"%f %f %f\n",&normal.x,&normal.y,&normal.z);
			temp_normals.push_back(normal);
		}
		else if(strcmp(lineHeader,"f") == 0)
		{
			std::string vertex1,vertex2,vertex3;
			unsigned int vertexIndex[3],uvIndex[3],normalIndex[3];
			int matches = fscanf(file,"%d/%d/%d %d/%d/%d %d/%d/%d\n",&vertexIndex[0], &uvIndex[0], &normalIndex[0], &vertexIndex[1], &uvIndex[1], &normalIndex[1], &vertexIndex[2], &uvIndex[2], &normalIndex[2] );
			if (matches != 9)
			{
				printf("File can't be read by our simple parser :-( Try exporting with other options\n");
				return false;
			}
			vertexIndices.push_back(vertexIndex[0]);
			vertexIndices.push_back(vertexIndex[1]);
			vertexIndices.push_back(vertexIndex[2]);
			uvIndices    .push_back(uvIndex[0]);
			uvIndices    .push_back(uvIndex[1]);
			uvIndices    .push_back(uvIndex[2]);
			normalIndices.push_back(normalIndex[0]);
			normalIndices.push_back(normalIndex[1]);
			normalIndices.push_back(normalIndex[2]);

		}
		else
		{
			// Probably a comment, eat up the rest of the line
			char stupidBuffer[1000];
			fgets(stupidBuffer, 1000, file);
		}
		
		

	}

	for( unsigned int i=0; i<vertexIndices.size(); i++ ){

		// Get the indices of its attributes
		unsigned int vertexIndex = vertexIndices[i];
		unsigned int uvIndex = uvIndices[i];
		unsigned int normalIndex = normalIndices[i];

		// Get the attributes thanks to the index
		glm::vec3 vertex = temp_vertices[ vertexIndex-1 ];
		glm::vec2 uv = temp_uvs[ uvIndex-1 ];
		glm::vec3 normal = temp_normals[ normalIndex-1 ];

		// Put the attributes in buffers
		out_vertices.push_back(vertex);
		out_uvs     .push_back(uv);
		out_normals .push_back(normal);
	}
	return true;

}