将单个未唱的 int 发送到 VBO

Sending single unsinged int to VBO

本文关键字：VBO int 单个未      更新时间：2023-10-16

我正在尝试向 vbo 发送一个无符号的 int，但是当我在顶点着色器(应该是 1(中测试其值时，该值与预期的值不同。

包含我的无符号整数的变量是 textureIds

加载 vbo 的代码：

std::vector<unsigned int> textureIds;
glGenBuffers(1, &vboID_m);
glBindBuffer(GL_ARRAY_BUFFER, vboID_m);
{
glBufferData(GL_ARRAY_BUFFER,
(vertices.size() + texture.size() + normals.size())
* sizeof(float) + textureIds.size() * sizeof(unsigned int), 0,
GL_STATIC_DRAW);
glBufferSubData(GL_ARRAY_BUFFER, 0, vertices.size() * sizeof(float),
vertices.data());
glBufferSubData(GL_ARRAY_BUFFER, vertices.size() * sizeof(float),
texture.size() * sizeof(float), texture.data());
glBufferSubData(GL_ARRAY_BUFFER,
(vertices.size() + texture.size()) * sizeof(float),
normals.size() * sizeof(float), normals.data());
glBufferSubData(GL_ARRAY_BUFFER,
(vertices.size() + texture.size() + normals.size()) * sizeof(float),
textureIds.size() * sizeof(unsigned int), textureIds.data());
}
glBindBuffer(GL_ARRAY_BUFFER, 0);

绘制 vbo 的代码：

void Chunck::draw() const {
glBindBuffer(GL_ARRAY_BUFFER, vboID_m);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float),
BUFFER_OFFSET(0));
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float),
BUFFER_OFFSET(verticeSize_m * sizeof(float)));
glEnableVertexAttribArray(1);
glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float),
BUFFER_OFFSET(
(verticeSize_m + textureSize_m) * sizeof(float)));
glEnableVertexAttribArray(2);
glVertexAttribPointer(3, 1, GL_UNSIGNED_INT, GL_FALSE, sizeof(unsigned int),
BUFFER_OFFSET(
(verticeSize_m + textureSize_m + normalSize_m) * sizeof(float)));
glEnableVertexAttribArray(3);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, grassTexture_m.getID());
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, dirtTexture_m.getID());
glDrawArrays(GL_TRIANGLES, 0, verticeSize_m / 3);
glBindTexture(GL_TEXTURE_2D, 0);
glDisableVertexAttribArray(2);
glDisableVertexAttribArray(1);
glDisableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
}

顶点着色器：

#version 330 core
in vec3 in_Vertex;
in vec2 in_TexCoord0;
in vec3 in_normal;
in int in_textureId;
uniform mat4 projection;
uniform mat4 model;
uniform mat4 view;
out vec2 coordTexture;
out vec3 normal;
out vec3 FragPos;
out vec3 rayDir;
out float grassAmount;
out float dirtAmount;

void main()
{
vec4 pos = model * vec4(in_Vertex, 1.0);
vec2 mu = vec2(0., 0.);
//pos.y = max(pos.y, 10 * exp(-((pos.x - mu.x) * (pos.x - mu.x) + (pos.z - mu.y) * (pos.z - mu.y)) / 100.));
gl_Position = projection * view * pos;
FragPos = vec3(pos);
coordTexture = in_TexCoord0;
normal = in_normal;
rayDir = (view * model * vec4(FragPos, 1.)).xyz;
grassAmount = 0;
dirtAmount = 0;
if (in_textureId == 0)
grassAmount = 1;
else if (in_textureId == 1)
dirtAmount = 1;
}

我应该输入第二个如果，但它没有：\

在定义通用顶点属性数据数组时，必须使用glVertexAttribIPointer(专注于I(，用于顶点属性in int in_textureId;。
由glVertexAttribPointer定义的顶点属性数据将转换为浮点型。

请参阅 OpenGL 4.6 API 核心配置文件规范;10.2. 当前顶点属性值;344 页

VertexAttribI*命令指定有符号或无符号定点值 分别存储为有符号整数或无符号整数。此类值称为纯整数。

。

所有其他VertexAttrib*命令指定直接转换为内部浮点表示形式的值。

请注意，应使用任一布局限定符在顶点着色器中指定属性索引：

layout(location = 0) in vec3 in_Vertex;
layout(location = 1) in vec2 in_TexCoord0;
layout(location = 2) in vec3 in_normal;
layout(location = 3) in int in_textureId;

或者，您应该在程序已链接glGetAttribLocation请求属性索引：

例如：

GLuint progObj = ...;
glLinkProgram( progObj );
GLint texIdInx = glGetAttribLocation( progObj, "in_textureId" );


glVertexAttribIPointer(
texIdInx, 1, GL_UNSIGNED_INT, GL_FALSE, sizeof(unsigned int),
BUFFER_OFFSET((verticeSize_m + textureSize_m + normalSize_m) * sizeof(float)));
glEnableVertexAttribArray(texIdInx );

编辑：

当然，glBindAttribLocation也是一个合适的解决方案。

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