llpatchvertexarray.h

Go to the documentation of this file.

#ifndef LL_LLPATCHVERTEXARRAY_H
#define LL_LLPATCHVERTEXARRAY_H

// A LLPatchVertexArray is really just a structure of vertex arrays for
// rendering a "patch" of a certain size.
//
// A "patch" is currently a sub-square of a larger square array of data
// we call a "surface".
class LLPatchVertexArray 
{
public:
        LLPatchVertexArray();
        LLPatchVertexArray(U32 surface_width, U32 patch_width, F32 meters_per_grid);   
        virtual ~LLPatchVertexArray();

        void create(U32 surface_width, U32 patch_width, F32 meters_per_grid); 
        void destroy();
        void init();

public:
        U32 mSurfaceWidth;      // grid points on one side of a LLSurface
        U32 mPatchWidth;        // grid points on one side of a LLPatch
        U32 mPatchOrder;        // 2^mPatchOrder >= mPatchWidth

        U32 *mRenderLevelp;     // Look-up table  : render_stride -> render_level
        U32 *mRenderStridep; // Look-up table : render_level -> render_stride

        // We want to be able to render a patch from multiple resolutions.
        // The lowest resolution has two triangles, and the highest has 
        // 2*mPatchWidth*mPatchWidth triangles. 
        //
        // mPatchWidth is not hard-coded, so we don't know how much memory 
        // to allocate to the vertex arrays until it is set.  Once it is
        // set, we will calculate how much total memory to allocate for the
        // vertex arrays, and then keep track of their lengths and locations 
        // in the memory bank.
        // 
        // A Patch has three regions that need vertex arrays: middle, north, 
        // and east.  For each region there are three items that must be 
        // kept track of: data, offset, and length.
};

#endif

---