所以我正在组装一个高度图渲染器,它将在顶点着色器中完成大部分工作,但首先我当然会生成一个要渲染的网格,目前我正在玩弄 openGL 的上限和C++ 以查看我可以渲染多密的网格(因此我稍后在 LoD 网格划分方面有一些东西要处理)
无论如何!切入问题;
我在测试 32、64 和 128 的 meshResolution 后注意到的问题我遇到了运行时崩溃,我通过使用一个自制的类“indexFace”来阻止它们,它包含 6 个索引来降低数组长度,问题是在 128分辨率只有三分之一的网格实际显示,我想知道 openGL 使用一组 BufferObjects 可以渲染或保存的索引数量是否有限制,或者它是否与我处理 C++ 方面的事情有关。
我通过以下方式生成网格:
void HeightMapMesh::GenerateMesh(GLfloat meshScale, GLushort meshResolution)
{
GLushort vertexCount = (meshResolution + 1) * (meshResolution + 1);
Vertex_Texture* vertexData = new Vertex_Texture[vertexCount];
GLushort indexCount = (meshResolution * meshResolution) * 6;
//indexFace holds 6 GLushort's in an attempt to overcome the array size limit
indexFace* indexData = new indexFace[meshResolution * meshResolution];
GLfloat scalar = meshScale / ((GLfloat)meshResolution);
GLfloat posX = 0;
GLfloat posY = 0;
for (int x = 0; x <= meshResolution; x++)
{
posX = ((GLfloat)x) * scalar;
for (int y = 0; y <= meshResolution; y++)
{
posY = ((GLfloat)y) * scalar;
vertexData[y + (x * (meshResolution + 1))] = Vertex_Texture(posX, posY, 0.0f, x, y);
}
}
GLint indexPosition;
GLint TL, TR, BL, BR;
for (int x = 0; x < meshResolution; x++)
{
for (int y = 0; y < meshResolution; y++)
{
indexPosition = (y + (x * (meshResolution)));
BL = y + (x * (meshResolution + 1));
TL = y + 1 + (x * (meshResolution + 1));
BR = y + ((x + 1) * (meshResolution + 1));
TR = y + 1 + ((x + 1) * (meshResolution + 1));
indexData[indexPosition] = indexFace(
BL, TR, TL,
BL, BR, TR
);
}
}
mesh.Fill(vertexData, vertexCount, (void *)indexData, indexCount, GL_STATIC_DRAW, GL_STATIC_DRAW);
delete [] vertexData;
delete [] indexData;
}
//This is for mesh.Fill()
void Fill(T* vertData, GLushort vertCount, void* indData, GLushort indCount, GLenum vertUsage, GLenum indUsage)
{
indexCount = indCount;
vertexCount = vertCount;
glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObjectID);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBufferObjectID);
glBufferData(GL_ARRAY_BUFFER, sizeof(T) * vertexCount, vertData, vertUsage);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLushort) * indexCount, indData, indUsage);
}
最佳答案
这是因为你做空了指数。
例如:GLushort indexCount = (meshResolution * meshResolution) * 6;
在 meshResolution
的值 105 处达到 USHRT_MAX。 (105*105*6 = 66150 > 65535)
使用整数作为索引。因此,将所有位置的索引更改为无符号整数,然后像这样进行最终的绘图调用:
glDrawElements( GL_QUADS, indCount, GL_UNSIGNED_INT, indices); //do this
//glDrawElements( GL_QUADS, indCount, GL_UNSIGNED_SHORT, indices); //instead of this
//also GL_QUADS is deprecated but it seems your data is in that format so I left it that way
如果您改为绘制 GL_TRIANGLE_STRIP
或更好地在 GPU 上进行曲面 segmentation ,则可以保存大量索引,因为这就像它的完美用例。
关于C++ OpenGL 大型网格缺少三角形,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26425463/