【OpenGL】平面着色器实例代码

 

// FlatShader.cpp
// OpenGL SuperBible
// Demonstrates a simple flat shader with transformations
// Program by Richard S. Wright Jr.
#pragma comment(lib, "gltools.lib")
#include <GLTools.h>	// OpenGL toolkit
#include <GLMatrixStack.h>
#include <GLFrame.h>
#include <GLFrustum.h>
#include <GLGeometryTransform.h>
#include <StopWatch.h>

#include <math.h>
#ifdef __APPLE__
#include <glut/glut.h>
#else
#define FREEGLUT_STATIC
#include <GL/glut.h>
#endif


GLFrame             viewFrame;
GLFrustum           viewFrustum;
GLTriangleBatch     torusBatch;
GLMatrixStack       modelViewMatrix;
GLMatrixStack       projectionMatrix;
GLGeometryTransform transformPipeline;

GLuint	flatShader;			// The Flat shader

GLint	locMVP;				// The location of the ModelViewProjection matrix uniform
GLint   locColor;			// The location of the color value uniform



// This function does any needed initialization on the rendering
// context. 
void SetupRC(void)
{
	// Background
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);

	glEnable(GL_DEPTH_TEST);
	glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);

	viewFrame.MoveForward(4.0f);

	// Make the torus
	gltMakeTorus(torusBatch, .80f, 0.25f, 52, 26);

	flatShader = gltLoadShaderPairWithAttributes("FlatShader.vp", "FlatShader.fp", 1, GLT_ATTRIBUTE_VERTEX, "vVertex");

	locMVP = glGetUniformLocation(flatShader, "mvpMatrix");
	locColor = glGetUniformLocation(flatShader, "vColorValue");
}

// Cleanup
void ShutdownRC(void)
{

}


// Called to draw scene
void RenderScene(void)
{
	static CStopWatch rotTimer;

	// Clear the window and the depth buffer
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	modelViewMatrix.PushMatrix(viewFrame);
	modelViewMatrix.Rotate(rotTimer.GetElapsedSeconds() * 10.0f, 0.0f, 1.0f, 0.0f);

	GLfloat vColor[] = { 0.1f, 0.1f, 1.f, 1.0f };

	glUseProgram(flatShader);
	glUniform4fv(locColor, 1, vColor);
	glUniformMatrix4fv(locMVP, 1, GL_FALSE, transformPipeline.GetModelViewProjectionMatrix());
	torusBatch.Draw();

	modelViewMatrix.PopMatrix();


	glutSwapBuffers();
	glutPostRedisplay();
}



void ChangeSize(int w, int h)
{
	// Prevent a divide by zero
	if (h == 0)
		h = 1;

	// Set Viewport to window dimensions
	glViewport(0, 0, w, h);

	viewFrustum.SetPerspective(35.0f, float(w) / float(h), 1.0f, 100.0f);

	projectionMatrix.LoadMatrix(viewFrustum.GetProjectionMatrix());
	transformPipeline.SetMatrixStacks(modelViewMatrix, projectionMatrix);
}

///
// Main entry point for GLUT based programs
int main(int argc, char* argv[])
{
	gltSetWorkingDirectory(argv[0]);

	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH | GLUT_STENCIL);
	glutInitWindowSize(800, 600);
	glutCreateWindow("Simple Transformed Geometry");
	glutReshapeFunc(ChangeSize);
	glutDisplayFunc(RenderScene);

	GLenum err = glewInit();
	if (GLEW_OK != err) {
		fprintf(stderr, "GLEW Error: %s\n", glewGetErrorString(err));
		return 1;
	}

	SetupRC();
	glutMainLoop();
	ShutdownRC();
	return 0;
}

OpenGL案例代码发现的问题：

1、ShutdownRC函数没有glDeleteProgram(flatShader);
2、RenderScene函数中一直在创建vColor一维数组