多重纹理

Res/test.fs

@@ -2,9 +2,10 @@
 precision mediump float;
 #endif
 uniform sampler2D U_Texture;
+uniform sampler2D U_Texture2;
 varying vec4 V_Color;
 varying vec2 V_Texcoord;
 void main()
 {
-	gl_FragColor=V_Color*texture2D(U_Texture,V_Texcoord);
+	gl_FragColor=V_Color*texture2D(U_Texture,V_Texcoord)*texture2D(U_Texture2,V_Texcoord);
 }

scene.cpp

@@ -3,7 +3,6 @@
 #include "utils.h"
 #include "ground.h"
 
-GLuint texture;
 glm::mat4 modelMatrix, viewMatrix, projectionMatrix;
 Ground ground;
 GLint textureLocation;
@@ -30,13 +29,11 @@ void Init() {
 	/* ³õʼ»¯ shader */
 	shader = new Shader;
 	shader->Init("Res/test.vs", "Res/test.fs");
-
-	textureLocation = glGetUniformLocation(shader->mProgram, "U_Texture");
+	shader->SetTexture("U_Texture", "Res/test.bmp");
+	shader->SetTexture("U_Texture2", "Res/test2.bmp");
 
 	modelMatrix = glm::translate(0.0f, 0.0f, -0.6f);
 
-	texture = CreateTexture2DFromBMP("Res/test.bmp");
-
 	ground.Init();
 }
 void SetViewPortSize(float width, float height) {
@@ -51,8 +48,6 @@ void Draw() {
 
 	vertexbuffer->Bind();
 	shader->Bind(glm::value_ptr(modelMatrix), glm::value_ptr(viewMatrix), glm::value_ptr(projectionMatrix));
-	glBindTexture(GL_TEXTURE_2D, texture);
-	glUniform1i(textureLocation, 0);
 	glDrawArrays(GL_TRIANGLES, 0, 3);
 	vertexbuffer->Unbind();
 }

shader.cpp

@@ -36,6 +36,13 @@ void Shader::Bind(float *M, float *V, float*P) {
 	glUniformMatrix4fv(mViewMatrixLocation, 1, GL_FALSE, V);
 	glUniformMatrix4fv(mProjectionMatrixLocation, 1, GL_FALSE, P);
 
+	int iIndex = 0;
+	for (auto iter = mUniformTextures.begin(); iter != mUniformTextures.end(); ++iter) {
+		glActiveTexture(GL_TEXTURE0 + iIndex);
+		glBindTexture(GL_TEXTURE_2D, iter->second->mTexture);
+		glUniform1i(iter->second->mLocation, iIndex++);
+	}
+
 	glEnableVertexAttribArray(mPositionLocation);
 	glVertexAttribPointer(mPositionLocation, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), 0);
 
@@ -48,3 +55,19 @@ void Shader::Bind(float *M, float *V, float*P) {
 	glEnableVertexAttribArray(mNormalLocation);
 	glVertexAttribPointer(mNormalLocation, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)(sizeof(float) * 12));
 }
+void Shader::SetTexture(const char * name, const char*imagePath) {
+	auto iter = mUniformTextures.find(name);
+	if (iter == mUniformTextures.end()) {
+		GLint location = glGetUniformLocation(mProgram, name);
+		if (location != -1) {
+			UniformTexture* t = new UniformTexture;
+			t->mLocation = location;
+			t->mTexture = CreateTexture2DFromBMP(imagePath);
+			mUniformTextures.insert(std::pair<std::string, UniformTexture*>(name, t));
+		}
+	}
+	else {
+		glDeleteTextures(1, &iter->second->mTexture);
+		iter->second->mTexture = CreateTexture2DFromBMP(imagePath);
+	}
+}

shader.h

@@ -1,10 +1,20 @@
 #pragma once
 #include "ggl.h"
+struct UniformTexture {
+	GLint mLocation;
+	GLuint mTexture;
+	UniformTexture() {
+		mLocation = -1;
+		mTexture = 0;
+	}
+};
 class Shader {
 public:
 	GLuint mProgram;
+	std::map<std::string, UniformTexture*> mUniformTextures;
 	GLint mModelMatrixLocation, mViewMatrixLocation, mProjectionMatrixLocation;
 	GLint mPositionLocation, mColorLocation, mTexcoordLocation, mNormalLocation;
 	void Init(const char*vs, const char*fs);
 	void Bind(float *M, float *V, float*P);
+	void SetTexture(const char * name, const char*imagePath);
 };