thorvg/src/renderer/gl_engine/tvgGlGeometry.cpp

/*
 * Copyright (c) 2020 - 2025 the ThorVG project. All rights reserved.

 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:

 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include "tvgGlCommon.h"
#include "tvgGlGpuBuffer.h"
#include "tvgGlTessellator.h"
#include "tvgGlRenderTask.h"

bool GlGeometry::tesselate(const RenderShape& rshape, RenderUpdateFlag flag)
{
    if (flag & (RenderUpdateFlag::Color | RenderUpdateFlag::Gradient | RenderUpdateFlag::Transform | RenderUpdateFlag::Path)) {
        fillVertex.clear();
        fillIndex.clear();

        BWTessellator bwTess{&fillVertex, &fillIndex};
        bwTess.tessellate(&rshape, mMatrix);
        mFillRule = rshape.rule;
        mBounds = bwTess.bounds();
    }

    if (flag & (RenderUpdateFlag::Stroke | RenderUpdateFlag::GradientStroke | RenderUpdateFlag::Transform)) {
        strokeVertex.clear();
        strokeIndex.clear();

        Stroker stroke{&strokeVertex, &strokeIndex, mMatrix};
        stroke.stroke(&rshape);
        mBounds = stroke.bounds();
    }

    return true;
}

bool GlGeometry::tesselate(const RenderSurface* image, RenderUpdateFlag flag)
{
    if (flag & RenderUpdateFlag::Image) {
        fillVertex.clear();
        fillIndex.clear();

        fillVertex.reserve(5 * 4);
        fillIndex.reserve(6);

        float left = 0.f;
        float top = 0.f;
        float right = image->w;
        float bottom = image->h;

        // left top point
        fillVertex.push(left);
        fillVertex.push(top);

        fillVertex.push(0.f);
        fillVertex.push(1.f);
        // left bottom point
        fillVertex.push(left);
        fillVertex.push(bottom);

        fillVertex.push(0.f);
        fillVertex.push(0.f);
        // right top point
        fillVertex.push(right);
        fillVertex.push(top);

        fillVertex.push(1.f);
        fillVertex.push(1.f);
        // right bottom point
        fillVertex.push(right);
        fillVertex.push(bottom);

        fillVertex.push(1.f);
        fillVertex.push(0.f);

        fillIndex.push(0);
        fillIndex.push(1);
        fillIndex.push(2);

        fillIndex.push(2);
        fillIndex.push(1);
        fillIndex.push(3);

        mBounds.x = 0;
        mBounds.y = 0;
        mBounds.w = image->w;
        mBounds.h = image->h;
    }

    return true;
}


void GlGeometry::disableVertex(uint32_t location)
{
    GL_CHECK(glDisableVertexAttribArray(location));
}


bool GlGeometry::draw(GlRenderTask* task, GlStageBuffer* gpuBuffer, RenderUpdateFlag flag)
{
    if (flag == RenderUpdateFlag::None) return false;

    Array<float>* vertexBuffer = nullptr;
    Array<uint32_t>* indexBuffer = nullptr;

    if ((flag & RenderUpdateFlag::Stroke) || (flag & RenderUpdateFlag::GradientStroke)) {
        vertexBuffer = &strokeVertex;
        indexBuffer = &strokeIndex;
    } else {
        vertexBuffer = &fillVertex;
        indexBuffer = &fillIndex;
    }

    if (indexBuffer->count == 0) return false;

    uint32_t vertexOffset = gpuBuffer->push(vertexBuffer->data, vertexBuffer->count * sizeof(float));
    uint32_t indexOffset = gpuBuffer->pushIndex(indexBuffer->data, indexBuffer->count * sizeof(uint32_t));

    // vertex layout
    if (flag & RenderUpdateFlag::Image) {
        // image has two attribute: [pos, uv]
        task->addVertexLayout(GlVertexLayout{0, 2, 4 * sizeof(float), vertexOffset});
        task->addVertexLayout(GlVertexLayout{1, 2, 4 * sizeof(float), vertexOffset + 2 * sizeof(float)});
    } else {
        task->addVertexLayout(GlVertexLayout{0, 2, 2 * sizeof(float), vertexOffset});
    }
    task->setDrawRange(indexOffset, indexBuffer->count);
    return true;
}


void GlGeometry::updateTransform(const Matrix& m)
{
    mMatrix = m;
}


void GlGeometry::setViewport(const RenderRegion& viewport)
{
    this->viewport = viewport;
}


const RenderRegion& GlGeometry::getViewport()
{
    return viewport;
}


const Matrix& GlGeometry::getTransformMatrix()
{
    return mMatrix;
}


GlStencilMode GlGeometry::getStencilMode(RenderUpdateFlag flag)
{
    if (flag & RenderUpdateFlag::Stroke) return GlStencilMode::Stroke;
    if (flag & RenderUpdateFlag::GradientStroke) return GlStencilMode::Stroke;
    if (flag & RenderUpdateFlag::Image) return GlStencilMode::None;

    if (mFillRule == FillRule::NonZero) return GlStencilMode::FillNonZero;
    if (mFillRule == FillRule::EvenOdd) return GlStencilMode::FillEvenOdd;

    return GlStencilMode::None;
}


RenderRegion GlGeometry::getBounds() const
{
    if (identity(&mMatrix)) {
        return mBounds;
    } else {
        Point lt{static_cast<float>(mBounds.x), static_cast<float>(mBounds.y)};
        Point lb{static_cast<float>(mBounds.x), static_cast<float>(mBounds.y + mBounds.h)};
        Point rt{static_cast<float>(mBounds.x + mBounds.w), static_cast<float>(mBounds.y)};
        Point rb{static_cast<float>(mBounds.x + mBounds.w), static_cast<float>(mBounds.y + mBounds.h)};

        lt *= mMatrix;
        lb *= mMatrix;
        rt *= mMatrix;
        rb *= mMatrix;

        float left = min(min(lt.x, lb.x), min(rt.x, rb.x));
        float top = min(min(lt.y, lb.y), min(rt.y, rb.y));
        float right = max(max(lt.x, lb.x), max(rt.x, rb.x));
        float bottom = max(max(lt.y, lb.y), max(rt.y, rb.y));

        auto bounds = RenderRegion {
            static_cast<int32_t>(floor(left)),
            static_cast<int32_t>(floor(top)),
            static_cast<int32_t>(ceil(right - floor(left))),
            static_cast<int32_t>(ceil(bottom - floor(top))),
        };
        if (bounds.w < 0 || bounds.h < 0) return mBounds;
        else return bounds;
    }
}