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Examples now support both 16 and 32 bit indices.

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This commit is contained in:
David Williams 2014-08-13 15:59:13 +02:00
parent d4118a2052
commit f1ed0c1be2
2 changed files with 13 additions and 9 deletions
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2
examples/common/OpenGLWidget.cpp
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@ -161,7 +161,7 @@ void OpenGLWidget::paintGL()
// Bind the vertex array for the current mesh
glBindVertexArray(meshData.vertexArrayObject);
// Draw the mesh
glDrawElements(GL_TRIANGLES, meshData.noOfIndices, GL_UNSIGNED_INT, 0);
glDrawElements(GL_TRIANGLES, meshData.noOfIndices, meshData.indexType, 0);
// Unbind the vertex array.
glBindVertexArray(0);
}

20
examples/common/OpenGLWidget.h
View File

@ -36,6 +36,7 @@ distribution.
struct OpenGLMeshData
{
GLuint noOfIndices;
GLenum indexType;
GLuint indexBuffer;
GLuint vertexBuffer;
GLuint vertexArrayObject;
@ -53,8 +54,8 @@ public:
OpenGLWidget(QWidget *parent);
// Convert a PolyVox mesh to OpenGL index/vertex buffers. Inlined because it's templatised.
template <typename DataType>
void addMesh(const PolyVox::Mesh< PolyVox::Vertex< DataType > >& surfaceMesh, const PolyVox::Vector3DInt32& translation = PolyVox::Vector3DInt32(0, 0, 0), float scale = 1.0f)
template <typename MeshType>
void addMesh(const MeshType& surfaceMesh, const PolyVox::Vector3DInt32& translation = PolyVox::Vector3DInt32(0, 0, 0), float scale = 1.0f)
{
// Convienient access to the vertices and indices
const auto& vecIndices = surfaceMesh.getIndices();
@ -71,29 +72,29 @@ public:
// The GL_ARRAY_BUFFER will contain the list of vertex positions
glGenBuffers(1, &(meshData.vertexBuffer));
glBindBuffer(GL_ARRAY_BUFFER, meshData.vertexBuffer);
glBufferData(GL_ARRAY_BUFFER, vecVertices.size() * sizeof(PolyVox::Vertex< DataType >), vecVertices.data(), GL_STATIC_DRAW);
glBufferData(GL_ARRAY_BUFFER, vecVertices.size() * sizeof(MeshType::VertexType), vecVertices.data(), GL_STATIC_DRAW);
// and GL_ELEMENT_ARRAY_BUFFER will contain the indices
glGenBuffers(1, &(meshData.indexBuffer));
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, meshData.indexBuffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, vecIndices.size() * sizeof(uint32_t), vecIndices.data(), GL_STATIC_DRAW);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, vecIndices.size() * sizeof(MeshType::IndexType), vecIndices.data(), GL_STATIC_DRAW);
// Every surface extractor outputs valid positions for the vertices, so tell OpenGL how these are laid out
glEnableVertexAttribArray(0); // Attrib '0' is the vertex positions
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(PolyVox::Vertex< DataType >), (GLvoid*)(offsetof(PolyVox::Vertex< DataType >, position))); //take the first 3 floats from every sizeof(decltype(vecVertices)::value_type)
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(MeshType::VertexType), (GLvoid*)(offsetof(MeshType::VertexType, position))); //take the first 3 floats from every sizeof(decltype(vecVertices)::value_type)
// Some surface extractors also generate normals, so tell OpenGL how these are laid out. If a surface extractor
// does not generate normals then nonsense values are written into the buffer here and sghould be ignored by the
// shader. This is mostly just to simplify this example code - in a real application you will know whether your
// chosen surface extractor generates normals and can skip uploading them if not.
glEnableVertexAttribArray(1); // Attrib '1' is the vertex normals.
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(PolyVox::Vertex< DataType >), (GLvoid*)(offsetof(PolyVox::Vertex< DataType >, normal)));
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(MeshType::VertexType), (GLvoid*)(offsetof(MeshType::VertexType, normal)));
// Finally a surface extractor will probably output additional data. This is highly application dependant. For this example code
// we're just uploading it as a set of bytes which we can read individually, but real code will want to do something specialised here.
glEnableVertexAttribArray(2); //We're talking about shader attribute '2'
GLint size = (std::min)(sizeof(DataType), size_t(4)); // Can't upload more that 4 components (vec4 is GLSL's biggest type)
glVertexAttribIPointer(2, size, GL_UNSIGNED_BYTE, sizeof(PolyVox::Vertex< DataType >), (GLvoid*)(offsetof(PolyVox::Vertex< DataType >, data)));
GLint size = (std::min)(sizeof(MeshType::VertexType::DataType), size_t(4)); // Can't upload more that 4 components (vec4 is GLSL's biggest type)
glVertexAttribIPointer(2, size, GL_UNSIGNED_BYTE, sizeof(MeshType::VertexType), (GLvoid*)(offsetof(MeshType::VertexType, data)));
// We're done uploading and can now unbind.
glBindVertexArray(0);
@ -103,6 +104,9 @@ public:
meshData.translation = QVector3D(translation.getX(), translation.getY(), translation.getZ());
meshData.scale = scale;
// Set 16 or 32-bit index buffer size.
meshData.indexType = sizeof(MeshType::IndexType) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT;
// Now add the mesh to the list of meshes to render.
addMeshData(meshData);
}