我正在尝试使用多个 VAO 和VBO在OpenGL中渲染多个对象。要使用相同的顶点渲染多个对象,我已经做过了,但我想做的是为每个对象使用不同的顶点,例如绘制一个正方形和一个圆形。对于一个正方形,我只需要6个顶点,但对于圆形,我需要360个顶点。我在阅读或创建着色器时出错。
以下是顶点着色器:
# version 330 core
layout (location = 0) in vec4 position;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
gl_Position = projection * view * model * position;
}
片段着色器:
# version 330 core
layout(location = 0) out vec4 color;
uniform vec4 u_Color;
void main()
{
color = u_Color;
}
VAO 和VBO的生成和绑定
// Circle
std::vector<VertexFormat> vertices;
for (int i = 0; i < 360; i++)
{
GLfloat angle = i * ((2.0f * 3.14159f) / 360);
vertices.push_back(VertexFormat(glm::vec3(cos(angle) * 100.0f, sin(angle) * 100.0f, 0.0f)));
}
// Pipette object
std::vector<VertexFormat> pipetteVertices;
pipetteVertices.push_back(VertexFormat(glm::vec3(injPipette.x + 500.0f, injPipette.y + 500.0f, 0.0f))); // 0
pipetteVertices.push_back(VertexFormat(glm::vec3(injPipette.x + 700.0f, injPipette.y + 500.0f, 0.0f))); // 1
pipetteVertices.push_back(VertexFormat(glm::vec3(injPipette.x + 700.0f, injPipette.y + 700.0f, 0.0f))); // 2
pipetteVertices.push_back(VertexFormat(glm::vec3(injPipette.x + 500.0f, injPipette.y + 700.0f, 0.0f))); // 3
pipetteVertices.push_back(VertexFormat(glm::vec3(injPipette.x + 500.0f, injPipette.y + 500.0f, 0.0f)));
pipetteVertices.push_back(VertexFormat(glm::vec3(injPipette.x + 700.0f, injPipette.y + 700.0f, 0.0f)));
GLuint vao;
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
GLuint vbo;
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(VertexFormat) * 6, &pipetteVertices[0], GL_STATIC_DRAW);
//Position attribute
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(VertexFormat), (GLvoid *)0);
GLuint vao2;
glGenVertexArrays(1, &vao2);
glBindVertexArray(vao2);
GLuint vbo2;
glGenBuffers(1, &vbo2);
glBindBuffer(GL_ARRAY_BUFFER, vbo2);
glBufferData(GL_ARRAY_BUFFER, sizeof(VertexFormat) * 360, &vertices[0], GL_STATIC_DRAW);
//Position attribute
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(VertexFormat), (GLvoid *) 0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
以及渲染循环中的绘制调用:
//Get the uniform locations of model, view and projection matrices
modelID = glGetUniformLocation(program, "model");
viewID = glGetUniformLocation(program, "view");
projectionID = glGetUniformLocation(program, "projection");
//View transform
glm::mat4 view = glm::lookAt(glm::vec3(0, 0, 2), glm::vec3(0, 0, 0), glm::vec3(0, 1, 0));
//Projection transform
//glm::mat4 projection = glm::perspective(45.0f, (GLfloat)screenWidth / (GLfloat)screenHeight, 0.1f, 1000.0f);
glm::mat4 projection = glm::ortho(0.0f, (GLfloat)screenWidth, 0.0f, (GLfloat)screenHeight, 0.1f, 10.0f);
{
glUniformMatrix4fv(viewID, 1, GL_FALSE, glm::value_ptr(view));
glUniformMatrix4fv(projectionID, 1, GL_FALSE, glm::value_ptr(projection));
glm::mat4 translate = glm::translate(glm::mat4(1.0), glm::vec3(100.0f + move_x, 100.0f + move_y, 0.0f));
glm::mat4 rotate = glm::rotate(glm::mat4(1.0), 0.0f, glm::vec3(0.0f, 0.0f, 1.0f));
glm::mat4 scale = glm::scale(glm::mat4(1.0), glm::vec3(1.0f, 1.0f, 2.0f));
glm::mat4 model = translate * rotate * scale;
glUniformMatrix4fv(modelID, 1, GL_FALSE, glm::value_ptr(model));
glUniform4f(color, 0.0f, 0.0f, 1.0f, 1.0f);
//Render
glDrawArrays(GL_TRIANGLE_FAN, 0, 360);
}
{
glUniformMatrix4fv(viewID, 1, GL_FALSE, glm::value_ptr(view));
glUniformMatrix4fv(projectionID, 1, GL_FALSE, glm::value_ptr(projection));
glm::mat4 translate = glm::translate(glm::mat4(1.0), glm::vec3(300.0f + injPipette.x, 300.0f + injPipette.y, 0.0f));
glm::mat4 rotate = glm::rotate(glm::mat4(1.0), 0.0f, glm::vec3(0.0f, 0.0f, 1.0f));
glm::mat4 scale = glm::scale(glm::mat4(1.0), glm::vec3(1.0f, 1.0f, 2.0f));
glm::mat4 model = translate * rotate * scale;
glUniformMatrix4fv(modelID, 1, GL_FALSE, glm::value_ptr(model));
glUniform4f(color, 1.0f, 0.0f, 0.0f, 0.5f);
//Render
glDrawArrays(GL_TRIANGLES, 0, 6);
}
我重复一遍,用相同的顶点绘制多个对象,我已经做到了。我需要知道如何用相同的顶点和片段着色器绘制多个对象,但顶点的数量不同。这个项目很小,最多只能在2D中渲染10个对象。
2条答案
按热度按时间vu8f3i0k1#
绘制命令(如
glDrawArrays
)处理并绘制在当前绑定的“顶点数组对象”中指定的通用顶点属性数据的数组。这意味着您需要在执行Draw调用之前绑定正确的vertex数组对象:
第一个
64jmpszr2#
我发现一个项目的代码: