OpenSubdiv/examples/glBatchViewer/delegate.cpp

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#if defined(__APPLE__)
    #include "TargetConditionals.h"
    #if TARGET_OS_IPHONE or TARGET_IPHONE_SIMULATOR
        #include <OpenGLES/ES2/gl.h>
    #else
        #include <OpenGL/gl3.h>
    #endif
#elif defined(ANDROID)
    #include <GLES2/gl2.h>
#else
    #if defined(_WIN32)
        #include <windows.h>
    #endif
    #include <GL/glew.h>
#endif

#include "delegate.h"

MyDrawContext::MyDrawContext() {
    glGenVertexArrays(1, &vao);
}

MyDrawContext::~MyDrawContext() {
    glDeleteVertexArrays(1, &vao);
}

MyDrawContext*
MyDrawContext::Create(OpenSubdiv::FarMesh<OpenSubdiv::OsdVertex> const *farMesh, bool requireFVarData)
{
    MyDrawContext *instance = new MyDrawContext();

    OpenSubdiv::FarPatchTables const * patchTables = farMesh->GetPatchTables();

    if (patchTables) {
        return Create(patchTables, requireFVarData);
    }

    delete instance;
    return NULL;
}

MyDrawContext*
MyDrawContext::Create(OpenSubdiv::FarPatchTables const *patchTables, bool requireFVarData)
{
    MyDrawContext * result = new MyDrawContext();

    if (patchTables) {
        if (result->create(patchTables, requireFVarData)) {
            return result;
        } else {
            delete result;
        }
    }
    return NULL;
}

// ----------------------------------------------------------------------------

void
MyDrawDelegate::BindBatch(OpenSubdiv::OsdUtilMeshBatchBase<MyDrawContext> *batch) {

    MyDrawContext *drawContext = batch->GetDrawContext();

    // bind vao
    glBindVertexArray(drawContext->vao);

    // bind vbo state
    // glBindVertexArray(batch->vao);
    glBindBuffer(GL_ARRAY_BUFFER, batch->BindVertexBuffer());
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, drawContext->patchIndexBuffer);

    // vertex attrib
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof (GLfloat) * 3, 0);

    // bind other builtin texture buffers
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_BUFFER, drawContext->vertexTextureBuffer);
    glActiveTexture(GL_TEXTURE1);
    glBindTexture(GL_TEXTURE_BUFFER, drawContext->vertexValenceTextureBuffer);
    glActiveTexture(GL_TEXTURE2);
    glBindTexture(GL_TEXTURE_BUFFER, drawContext->quadOffsetTextureBuffer);
    glActiveTexture(GL_TEXTURE3);
    glBindTexture(GL_TEXTURE_BUFFER, drawContext->ptexCoordinateTextureBuffer);
}

void
MyDrawDelegate::UnbindBatch(OpenSubdiv::OsdUtilMeshBatchBase<MyDrawContext> *batch) {

    glBindVertexArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
}

void
MyDrawDelegate::BindEffect(MyEffect &effect) {
    // cross-patch state
    // bind ptex etc
}

void
MyDrawDelegate::UnbindEffect(MyEffect &effect) {
}

void
MyDrawDelegate::DrawElements(MyEffect &effect, OpenSubdiv::OsdDrawContext::PatchArray const &patchArray) {

    // bind patchType-wise effect state
    // can be skipped (if config is not changed)
    MyDrawConfig *config = GetDrawConfig(effect, patchArray.GetDescriptor());

    GLuint program = config->program;

    if (true /* if config is different from previous call */) {
        glUseProgram(program);
        glPatchParameteri(GL_PATCH_VERTICES, patchArray.GetDescriptor().GetNumControlVertices());
        // bind patchArray state and draw
    }
    
    // apply patch color
    effect.BindDrawConfig(config, patchArray.GetDescriptor());
    
    glUniform1i(config->levelBaseUniform, patchArray.GetPatchIndex());
    if (patchArray.GetDescriptor().GetType() == OpenSubdiv::FarPatchTables::GREGORY ||
        patchArray.GetDescriptor().GetType() == OpenSubdiv::FarPatchTables::GREGORY_BOUNDARY){
        glUniform1i(config->gregoryQuadOffsetBaseUniform, patchArray.GetQuadOffsetIndex());
    }
    
    if (patchArray.GetDescriptor().GetType() == OpenSubdiv::FarPatchTables::QUADS) {
        glDrawElements(GL_LINES_ADJACENCY, patchArray.GetNumIndices(), GL_UNSIGNED_INT,
                       (void*)(patchArray.GetVertIndex()*sizeof(GLuint)));
    } else {
        glDrawElements(GL_PATCHES, patchArray.GetNumIndices(), GL_UNSIGNED_INT,
                       (void*)(patchArray.GetVertIndex()*sizeof(GLuint)));
    }
    _numDrawCalls++;
}

MyDrawConfig *
MyDrawDelegate::GetDrawConfig(MyEffect &effect, OpenSubdiv::OsdDrawContext::PatchDescriptor desc) {

    return _effectRegistry.GetDrawConfig(effect.GetEffectDescriptor(), desc);
}