OpenGL自制游戏引擎-着色器

1.在vertex shader中新增一个输出变量

代码语言：javascript复制

const char* vertexShaderSource =
"#version 330 core                                       n"
"layout (location = 0) in vec3 aPos;                     n"
"out vec4 vertexColor; n"
"void main()                                             n"
"{                                                       n"
"    gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);n"
"    vertexColor = vec4(1.0,1.0,0,1.0); n"
"}   n";

const char* fragmentShaderSource =
"#version 330 core                               n"
"in vec4 vertexColor; n"
"out vec4 FragColor;                             n"
"void main(){                                    n"
"    FragColor =vertexColor;}  n";

Uniform是一种从CPU的应用向GPU中的着色器发送数据的方式，uniform是全局的，uniform可以被着色器的任意阶段访问。 2.通过Uniform实现颜色渐变

代码语言：javascript复制

const char* fragmentShaderSource =
"#version 330 core                               n"
"in vec4 vertexColor; n"
"uniform vec4 ourColor; n"
"out vec4 FragColor;                             n"
"void main(){                                    n"
"    FragColor =ourColor;}  n";

代码语言：javascript复制

        float timeValue = glfwGetTime();
        float greenValue = (sin(timeValue) / 2.0f)   0.5f;
        int vertexColorLocation = glGetUniformLocation(shaderProgram, "ourColor"); 
        

        //glBindVertexArray(VAO);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
        glUseProgram(shaderProgram);

        glUniform4f(vertexColorLocation, 0, greenValue, 0, 1.0f);
        //glDrawArrays(GL_TRIANGLES, 0, 6);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

gpu shader 变量

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