GR_PrimTetra.C

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/*
 * Copyright (c) 2021
 *    Side Effects Software Inc.  All rights reserved.
 *
 * Redistribution and use of Houdini Development Kit samples in source and
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#include "GR_PrimTetra.h"
#include "GEO_PrimTetra.h"

#include <DM/DM_RenderTable.h>
#include <GR/GR_Utils.h>
#include <RE/RE_ElementArray.h>
#include <RE/RE_Geometry.h>
#include <RE/RE_LightList.h>
#include <RE/RE_ShaderHandle.h>
#include <RE/RE_VertexArray.h>

#include <GT/GT_GEOPrimitive.h>

using namespace HDK_Sample;

// See GEO_PrimTetra::registerMyself() for installation of the hook.

GR_PrimTetraHook::GR_PrimTetraHook()
    : GUI_PrimitiveHook("Tetrahedron")
{
}

GR_PrimTetraHook::~GR_PrimTetraHook()
{
}

GR_Primitive *
GR_PrimTetraHook::createPrimitive(const GT_PrimitiveHandle &gt_prim,
                                  const GEO_Primitive   *geo_prim,
                                  const GR_RenderInfo   *info,
                                  const char            *cache_name,
                                  GR_PrimAcceptResult  &processed)
{
    return new GR_PrimTetra(info, cache_name, geo_prim);
}

GR_PrimTetra::GR_PrimTetra(const GR_RenderInfo *info,
                           const char *cache_name,
                           const GEO_Primitive *prim)
    : GR_Primitive(info, cache_name, GA_PrimCompat::TypeMask(0))
{
   
    myID = prim->getTypeId().get();
    myGeo = NULL;
}

GR_PrimTetra::~GR_PrimTetra()
{
    delete myGeo;
}


GR_PrimAcceptResult
GR_PrimTetra::acceptPrimitive(GT_PrimitiveType t,
                              int geo_type,
                              const GT_PrimitiveHandle &ph,
                              const GEO_Primitive *prim)
{
    if(geo_type == myID)
        return GR_PROCESSED;
    
    return GR_NOT_PROCESSED;
}


void
GR_PrimTetra::update(RE_Render                 *r,
                     const GT_PrimitiveHandle  &primh,
                     const GR_UpdateParms      &p)
{
    // Fetch the GEO primitive from the GT primitive handle
    const GEO_PrimTetra *tet = NULL;
    
    // GL3 and above requires named vertex attributes, while GL2 and GL1 use
    // the older builtin names.
    
    const char *posname = "P";
    const char *nmlname = "N";
    RE_VertexArray *pos = NULL;
    RE_VertexArray *nml = NULL;
    UT_Vector3FArray pt;

    // Initialize the geometry with the proper name for the GL cache
    if(!myGeo)
        myGeo = new RE_Geometry;
    myGeo->cacheBuffers(getCacheName());

    getGEOPrimFromGT<GEO_PrimTetra>(primh, tet);

    const int num_tets =  tet ? 1 : 0;
    if(num_tets == 0)
    {
        delete myGeo;
        myGeo = NULL;
        return;
    }

    // Extract tetra point positions.
    {
        GU_DetailHandleAutoReadLock georl(p.geometry);
        const GU_Detail *dtl = georl.getGdp();
        
        for(int v=0; v<4; v++)
            pt.append(dtl->getPos3(dtl->vertexPoint(tet->getVertexOffset(v))));
    }

    // Initialize the number of points in the geometry.
    myGeo->setNumPoints( 12 * num_tets);

    GR_UpdateParms dp(p);
    const GR_Decoration pdecs[] = { GR_POINT_MARKER,
                                    GR_POINT_NUMBER,
                                    GR_POINT_NORMAL,
                                    GR_POINT_UV,
                                    GR_POINT_POSITION,
                                    GR_POINT_VELOCITY,
                                    GR_PRIM_NORMAL,
                                    GR_PRIM_NUMBER,
                                    GR_VERTEX_MARKER,
                                    GR_VERTEX_NORMAL,
                                    GR_VERTEX_NUMBER,
                                    GR_VERTEX_UV,
                                    GR_NO_DECORATION };
    myDecorRender->setupFromDisplayOptions(p.dopts, p.required_dec,
                                           dp, pdecs, GR_POINT_ATTRIB);

    
    // Fetch P (point position). If its cache version matches, no upload is
    // required.
    pos = myGeo->findCachedAttrib(r, posname, RE_GPU_FLOAT32, 3,
                                  RE_ARRAY_POINT, true);
    if(pos->getCacheVersion() != dp.geo_version)
    {
        // map() returns a pointer to the GL buffer
        UT_Vector3F *pdata = static_cast<UT_Vector3F *>(pos->map(r));
        if(pdata)
        {
            for(int t=0; t<num_tets; t++)
            {
                pdata[0] = pt(t*4);
                pdata[1] = pt(t*4+1);
                pdata[2] = pt(t*4+2);
            
                pdata[3] = pt(t*4);
                pdata[4] = pt(t*4+2);
                pdata[5] = pt(t*4+3);

                pdata[6] = pt(t*4+1);
                pdata[7] = pt(t*4+2);
                pdata[8] = pt(t*4+3);

                pdata[9] = pt(t*4);
                pdata[10] = pt(t*4+3);
                pdata[11] = pt(t*4+1);

                pdata += 12;
            }

            // unmap the buffer so it can be used by GL
            pos->unmap(r);
            
            // Always set the cache version after assigning data.
            pos->setCacheVersion(dp.geo_version);
        }
    }

    
    // NOTE: you can add more attributes from a detail, such as Cd, uv, Alpha
    //       by repeating the process above.

    // Fetch N (point normal). This just generates normals for the tetras.
    nml = myGeo->findCachedAttrib(r, nmlname, RE_GPU_FLOAT32, 3,
                                  RE_ARRAY_POINT, true);
    if(nml->getCacheVersion() != dp.geo_version)
    {
        UT_Vector3F *ndata = static_cast<UT_Vector3F *>(nml->map(r));
        if(ndata)
        {
            UT_Vector3F n0, n1, n2, n3;

            // This just creates primitive normals for the tet. It's currently
            // not 100% correct (FIXME).
            for(int t=0; t<num_tets; t++)
            {
                n0 = -cross(pt(t*4+2)-pt(t*4), pt(t*4+1)-pt(t*4)).normalize();
                n1 =  cross(pt(t*4+3)-pt(t*4), pt(t*4+2)-pt(t*4)).normalize();
                n2 = -cross(pt(t*4+3)-pt(t*4+1),pt(t*4+2)-pt(t*4+1)).normalize();
                n3 = -cross(pt(t*4+1)-pt(t*4), pt(t*4+3)-pt(t*4)).normalize();

                ndata[0] = ndata[1] = ndata[2] = n0;
                ndata[3] = ndata[4] = ndata[5] = n1;
                ndata[6] = ndata[7] = ndata[8] = n2;
                ndata[9] = ndata[10] = ndata[11] = n3;

                ndata += 12;
            }
            
            nml->unmap(r);

            // Always set the cache version after assigning data.
            nml->setCacheVersion(dp.geo_version);
        }
    }

    
    // Extra constant inputs for the GL3 default shaders we are using.
    // This isn't required unless 
    fpreal32 col[3] = { 1.0, 1.0, 1.0 };
    fpreal32 uv[2]  = { 0.0, 0.0 };
    fpreal32 alpha  = 1.0;
    fpreal32 pnt    = 0.0;
        
    myGeo->createConstAttribute(r, "Cd",    RE_GPU_FLOAT32, 3, col);
    myGeo->createConstAttribute(r, "uv",    RE_GPU_FLOAT32, 2, uv);
    myGeo->createConstAttribute(r, "Alpha", RE_GPU_FLOAT32, 1, &alpha);
    myGeo->createConstAttribute(r, "pointSelection", RE_GPU_FLOAT32, 1,&pnt);

    myInstancedFlag = 
        GR_Utils::buildInstanceObjectMatrix(r, primh, p, myGeo,
                                            p.instance_version, 0);
    UT_IntArray dummy;
    GR_Utils::buildInstanceIndex(r, myGeo, false, dummy, 0, 0);
    
    // Connectivity, for both shaded and wireframe
    myGeo->connectAllPrims(r, RE_GEO_WIRE_IDX, RE_PRIM_LINES, NULL, true);
    myGeo->connectAllPrims(r, RE_GEO_SHADED_IDX, RE_PRIM_TRIANGLES, NULL, true);
}


// GL3 shaders. These use some of the builtin Houdini shaders, which are
// described by the .prog file format - a simple container format for various
// shader stages and other information.

static RE_ShaderHandle theNQShader("material/GL32/beauty_lit.prog");
static RE_ShaderHandle theNQFlatShader("material/GL32/beauty_flat_lit.prog");
static RE_ShaderHandle theNQUnlitShader("material/GL32/beauty_unlit.prog");
static RE_ShaderHandle theHQShader("material/GL32/beauty_material.prog");
static RE_ShaderHandle theLineShader("basic/GL32/wire_color.prog");
static RE_ShaderHandle theConstShader("material/GL32/constant.prog");
static RE_ShaderHandle theZCubeShader("basic/GL32/depth_cube.prog");
static RE_ShaderHandle theZLinearShader("basic/GL32/depth_linear.prog");
static RE_ShaderHandle theMatteShader("basic/GL32/matte.prog");


void
GR_PrimTetra::render(RE_Render              *r,
                     GR_RenderMode           render_mode,
                     GR_RenderFlags          flags,
                     GR_DrawParms            dp)
{
    if(!myGeo)
        return;

    bool need_wire = (render_mode == GR_RENDER_WIREFRAME ||
                      render_mode == GR_RENDER_HIDDEN_LINE ||
                      render_mode == GR_RENDER_GHOST_LINE ||
                      render_mode == GR_RENDER_MATERIAL_WIREFRAME ||
                      (flags & GR_RENDER_FLAG_WIRE_OVER));
    
    // Shaded mode rendering
    if(render_mode == GR_RENDER_BEAUTY ||
       render_mode == GR_RENDER_MATERIAL ||
       render_mode == GR_RENDER_CONSTANT ||
       render_mode == GR_RENDER_HIDDEN_LINE ||
       render_mode == GR_RENDER_GHOST_LINE ||
       render_mode == GR_RENDER_DEPTH ||
       render_mode == GR_RENDER_DEPTH_LINEAR ||
       render_mode == GR_RENDER_DEPTH_CUBE ||
       render_mode == GR_RENDER_MATTE)
    {
        // enable polygon offset if doing a wireframe on top of shaded
        bool polyoff = r->isPolygonOffset();
        if(need_wire)
            r->polygonOffset(true);

        r->pushShader();

        // GL3 requires the use of shaders. The fixed function pipeline
        // GL builtins (which are deprecated, like gl_ModelViewMatrix)
        // are not initialized in the GL3 renderer.
            
        if(render_mode == GR_RENDER_BEAUTY)
        {
            if(flags & GR_RENDER_FLAG_UNLIT)
                r->bindShader(theNQUnlitShader);
            else if(flags & GR_RENDER_FLAG_FLAT_SHADED)
                r->bindShader(theNQFlatShader);
            else
                r->bindShader(theNQShader);
        }
        else if(render_mode == GR_RENDER_MATERIAL)
        {
            r->bindShader(theHQShader);
        }
        else if(render_mode == GR_RENDER_CONSTANT ||
                render_mode == GR_RENDER_DEPTH ||
                render_mode == GR_RENDER_HIDDEN_LINE ||
                render_mode == GR_RENDER_GHOST_LINE)
        {
            // Reuse constant for depth-only since it's so lightweight.
            r->bindShader(theConstShader);
        }
        else if(render_mode == GR_RENDER_DEPTH_LINEAR)
        {
            // Depth written to world-space Z instead of non-linear depth
            // buffer Z ([0..1] near-far depth range)
            r->bindShader(theZLinearShader);
        }
        else if(render_mode == GR_RENDER_DEPTH_CUBE)
        {
            // Linear depth written to 
            r->bindShader(theZCubeShader);
        }
        else if(render_mode == GR_RENDER_MATTE)
        {
            r->bindShader(theMatteShader);
        }

        
        // setup materials and lighting
        if(dp.materials && (dp.materials->getDefaultMaterial()  ||
                            dp.materials->getFactoryMaterial()))
        {
            RE_Shader *shader = r->getShader();
            RE_MaterialPtr mat = dp.materials->getDefaultMaterial();
            if(!mat)
                mat = dp.materials->getFactoryMaterial();
            
            // Set up lighting for any GL3 lighting blocks
            if(shader && dp.opts->getLightList())
                dp.opts->getLightList()->bindForShader(r, shader);

            // set up the main material block for GL3 
            mat->updateShaderForMaterial(r, 0, true, true,
                                         RE_SHADER_TARGET_TRIANGLE, shader);
        }

        // Draw call for the geometry
        if(dp.draw_instanced)
            myGeo->drawInstanceGroup(r, RE_GEO_SHADED_IDX, dp.instance_group);
        else
            myGeo->draw(r, RE_GEO_SHADED_IDX);

        if(r->getShader())
            r->getShader()->removeOverrideBlocks();
        r->popShader();

        if(need_wire && !polyoff)
            r->polygonOffset(polyoff);
    }


    // Wireframe rendering
    if(need_wire)
    {
        // GL3 requires a shader even for simple wireframe rendering.
        r->pushShader(theLineShader);

        if(dp.draw_instanced)
            myGeo->drawInstanceGroup(r, RE_GEO_WIRE_IDX, dp.instance_group);
        else
            myGeo->draw(r, RE_GEO_WIRE_IDX);

        r->popShader();
    }
}

void
GR_PrimTetra::renderDecoration(RE_Render *r,
                               GR_Decoration decor,
                               const GR_DecorationParms &p)
{
    drawDecorationForGeo(r, myGeo, decor, p.opts, p.render_flags,
                         p.overlay, p.override_vis, p.instance_group,
                         GR_SELECT_NONE);

}

int
GR_PrimTetra::renderPick(RE_Render *r,
                         const GR_DisplayOption *opt,
                         unsigned int pick_type,
                         GR_PickStyle pick_style,
                         bool has_pick_map)
{
    // This example is not pickable.
    return 0;
}