实例化的多维数据集只显示一次

Question

我正在尝试创建四个相邻的多维数据集。我想试试这些立方体的例子，因为我以后会画更多的立方体，而不是四个立方体。我一直在遵循一些不同的教程来创建一个有纹理的立方体：http://www.opengl-tutorial.org/beginners-tutorials/tutorial-5-a-textured-cube/然后实例化此多维数据集：https://learnopengl.com/Advanced-OpenGL/Instancing当我运行我的程序时，我只看到一个立方体。我用相机在窗口中移动，这样我就可以看到任何其他可能的立方体，这些立方体只显示一个立方体。

这是我的主要功能：

int main(){
if (!glfwInit()) {
std::cout << "Failed to initialize GLFW!" << std::endl;
}
//GLFWwindow* window;
int width = 1024; int height = 700;
window = glfwCreateWindow(width, height, "Paradise", NULL, NULL);
if (!window) {
std::cout << "Failed to initialize window!" << std::endl;
}
glfwMakeContextCurrent(window);
if (glewInit() != GLEW_OK) {
std::cout << "failed to initialize GLEW!" << std::endl;
}
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
static const GLfloat g_vertex_buffer_data[] = {
-1.0f,-1.0f,-1.0f, // triangle 1 : begin
-1.0f,-1.0f, 1.0f,
-1.0f, 1.0f, 1.0f, // triangle 1 : end
1.0f, 1.0f,-1.0f, // triangle 2 : begin
-1.0f,-1.0f,-1.0f,
-1.0f, 1.0f,-1.0f, // triangle 2 : end
1.0f,-1.0f, 1.0f,
-1.0f,-1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
1.0f, 1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f, 1.0f, 1.0f,
-1.0f, 1.0f,-1.0f,
1.0f,-1.0f, 1.0f,
-1.0f,-1.0f, 1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f, 1.0f, 1.0f,
-1.0f,-1.0f, 1.0f,
1.0f,-1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
1.0f,-1.0f,-1.0f,
1.0f, 1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
1.0f, 1.0f, 1.0f,
1.0f,-1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
1.0f, 1.0f,-1.0f,
-1.0f, 1.0f,-1.0f,
1.0f, 1.0f, 1.0f,
-1.0f, 1.0f,-1.0f,
-1.0f, 1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
-1.0f, 1.0f, 1.0f,
1.0f,-1.0f, 1.0f
};
static const GLfloat g_uv_buffer_data[] = {
0.000059f, 1.0f - 0.000004f,
0.000103f, 1.0f - 0.336048f,
0.335973f, 1.0f - 0.335903f,
1.000023f, 1.0f - 0.000013f,
0.667979f, 1.0f - 0.335851f,
0.999958f, 1.0f - 0.336064f,
0.667979f, 1.0f - 0.335851f,
0.336024f, 1.0f - 0.671877f,
0.667969f, 1.0f - 0.671889f,
1.000023f, 1.0f - 0.000013f,
0.668104f, 1.0f - 0.000013f,
0.667979f, 1.0f - 0.335851f,
0.000059f, 1.0f - 0.000004f,
0.335973f, 1.0f - 0.335903f,
0.336098f, 1.0f - 0.000071f,
0.667979f, 1.0f - 0.335851f,
0.335973f, 1.0f - 0.335903f,
0.336024f, 1.0f - 0.671877f,
1.000004f, 1.0f - 0.671847f,
0.999958f, 1.0f - 0.336064f,
0.667979f, 1.0f - 0.335851f,
0.668104f, 1.0f - 0.000013f,
0.335973f, 1.0f - 0.335903f,
0.667979f, 1.0f - 0.335851f,
0.335973f, 1.0f - 0.335903f,
0.668104f, 1.0f - 0.000013f,
0.336098f, 1.0f - 0.000071f,
0.000103f, 1.0f - 0.336048f,
0.000004f, 1.0f - 0.671870f,
0.336024f, 1.0f - 0.671877f,
0.000103f, 1.0f - 0.336048f,
0.336024f, 1.0f - 0.671877f,
0.335973f, 1.0f - 0.335903f,
0.667969f, 1.0f - 0.671889f,
1.000004f, 1.0f - 0.671847f,
0.667979f, 1.0f - 0.335851f
};
GLuint Texture = loadBMP_custom("uvtemplate.bmp");
const int cubeAmount = 4;
glm::vec2 cubes[cubeAmount];
int index = 0;
//float offset = 0.1f;
for (int x = 0; x < cubeAmount; x++) {
std::cout << x << std::endl;
glm::vec2 translation;
translation.x = (float)x / 10.0f; // divide by ten so 3 become 0.3 creates less space
cubes[index++] = translation;
}
GLuint programID = LoadShaders("Shader.vs", "Shader.fs");
//store instanced data in an array buffer
unsigned int instanceVBO;
glGenBuffers(1, &instanceVBO);
glBindBuffer(GL_ARRAY_BUFFER, instanceVBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(glm::vec2)* cubeAmount, &cubes[0], GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
GLuint vertexbuffer;
glGenBuffers(1, &vertexbuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW);
GLuint texturebuffer;
glGenBuffers(1, &texturebuffer);
glBindBuffer(GL_ARRAY_BUFFER, texturebuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(g_uv_buffer_data), g_uv_buffer_data, GL_STATIC_DRAW);
glEnableVertexAttribArray(2);
glBindBuffer(GL_ARRAY_BUFFER, instanceVBO);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), (void*)0);
glBindBuffer(GL_ARRAY_BUFFER, 1);
glVertexAttribDivisor(2, 1);

glEnable(GL_CULL_FACE);
while (!glfwWindowShouldClose(window)) {
glClearColor(0.0f / 255.0f, 170.0f / 255.0f, 204.0f / 255.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(programID);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
glVertexAttribPointer(
0,
3, GL_FLOAT, GL_FALSE,
0,
(void*)0
);
computeMatricesFromInputs();
glm::mat4 ProjectionMatrix = getProjectionMatrix();
glm::mat4 ViewMatrix = getViewMatrix();
glm::mat4 ModelMatrix = glm::mat4(1.0);
glm::mat4 MVP = ProjectionMatrix * ViewMatrix * ModelMatrix;
GLuint MatrixID = glGetUniformLocation(programID, "MVP");
glUniformMatrix4fv(MatrixID, 1, GL_FALSE, &MVP[0][0]);
//glDrawArrays(GL_TRIANGLES, 0, 12*3);
glDrawArraysInstanced(GL_TRIANGLES, 0, 12 * 3, 4);
glDisableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glBindBuffer(GL_ARRAY_BUFFER, texturebuffer);
glVertexAttribPointer(
1,
2,
GL_FLOAT,
GL_FALSE,
0,
(void*)0
);
glfwSwapBuffers(window);
glfwPollEvents();
}
}

顶点着色器：

#version 330 core
layout(location = 0) in vec3 vertexPosition_modelspace;
layout(location = 1) in vec2 vertexUV;
out vec2 UV;
uniform mat4 MVP;
void main(){
gl_Position = MVP * vec4(vertexPosition_modelspace,1);
UV = vertexUV;
}

片段着色器：

#version 440 core
in vec2 UV;
out vec3 color;
uniform sampler2D myTextureSampler;
void main(){
color = texture( myTextureSampler, UV ).rgb;
}

我认为这可能是因为所有四个立方体都在同一位置，我尝试通过更改来更改每个立方体的位置

for (int x = 0; x < cubeAmount; x++) {
std::cout << x << std::endl;
glm::vec2 translation;
translation.x = (float)x / 10.0f;
cubes[index++] = translation;
}

到此：

for (int x = 0; x < cubeAmount; x++) {
std::cout << x << std::endl;
glm::vec2 translation;
translation.x = (float)x / 20.0f;
cubes[index++] = translation;
}

希望这能改变立场。这只会将单个多维数据集移动到另一个位置，而不会显示任何其他多维数据集。我在这里做错了什么？

Answer 1

您必须在每个实例中使用不同的MVP矩阵，正如我在回答您之前的问题时提到的，将立方体实例化为相邻的OpenGL。

或者，可以根据顶点着色器中的gl_InstanceID计算平移。例如：

#version 330 core
layout(location = 0) in vec3 vertexPosition_modelspace;
layout(location = 1) in vec2 vertexUV;
out vec2 UV;
uniform mat4 MVP;
void main(){
const float offset = 0.1; // this is just a guess, probably you have to adapt it
vec3 pos = vertexPosition_modelspace;
pos.x += float(gl_InstanceID) * offset;
gl_Position = MVP * vec4(pos, 1.0);
UV = vertexUV;
}