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#include "stream_video_node.h"

#include <QtQuick/qsgtexture.h>

namespace QtWebEngineCore {

class StreamVideoMaterialShader : public QSGMaterialShader
{
public:
    StreamVideoMaterialShader(TextureTarget target) : m_target(target) { }
    virtual void updateState(const RenderState &state, QSGMaterial *newMaterial, QSGMaterial *oldMaterial) override;

    char const *const *attributeNames() const override {
        static const char *names[] = {
            "a_position",
            "a_texCoord",
            0
        };
        return names;
    }

protected:
    const char *vertexShader() const override {
        // Keep in sync with cc::VertexShaderVideoTransform
        static const char *shader =
        "attribute highp vec4 a_position;\n"
        "attribute mediump vec2 a_texCoord;\n"
        "uniform highp mat4 matrix;\n"
        "uniform highp mat4 texMatrix;\n"
        "varying mediump vec2 v_texCoord;\n"
        "void main() {\n"
        "  gl_Position = matrix * a_position;\n"
        "  v_texCoord = vec4(texMatrix * vec4(a_texCoord.x, 1.0 - a_texCoord.y, 0.0, 1.0)).xy;\n"
        "}";
        return shader;
    }

    const char *fragmentShader() const override {
        // Keep in sync with cc::FragmentShaderRGBATexAlpha
        static const char *shaderExternal  =
        "#extension GL_OES_EGL_image_external : require\n"
        "varying mediump vec2 v_texCoord;\n"
        "uniform samplerExternalOES s_texture;\n"
        "uniform lowp float alpha;\n"
        "void main() {\n"
        "  lowp vec4 texColor = texture2D(s_texture, v_texCoord);\n"
        "  gl_FragColor = texColor * alpha;\n"
        "}";
        static const char *shader2DRect =
        "#extension GL_ARB_texture_rectangle : require\n"
        "varying mediump vec2 v_texCoord;\n"
        "uniform sampler2DRect s_texture;\n"
        "uniform lowp float alpha;\n"
        "void main() {\n"
        "  lowp vec4 texColor = texture2DRect(s_texture, v_texCoord);\n"
        "  gl_FragColor = texColor * alpha;\n"
        "}";
        if (m_target == ExternalTarget)
            return shaderExternal;
        else
            return shader2DRect;
    }

    virtual void initialize() override {
        m_id_matrix = program()->uniformLocation("matrix");
        m_id_sTexture = program()->uniformLocation("s_texture");
        m_id_texMatrix = program()->uniformLocation("texMatrix");
        m_id_opacity = program()->uniformLocation("alpha");
    }

    int m_id_matrix;
    int m_id_texMatrix;
    int m_id_sTexture;
    int m_id_opacity;
    TextureTarget m_target;
};

void StreamVideoMaterialShader::updateState(const RenderState &state, QSGMaterial *newMaterial, QSGMaterial *oldMaterial)
{
    Q_UNUSED(oldMaterial);

    StreamVideoMaterial *mat = static_cast<StreamVideoMaterial *>(newMaterial);
    program()->setUniformValue(m_id_sTexture, 0);

    mat->m_texture->bind();

    if (state.isOpacityDirty())
        program()->setUniformValue(m_id_opacity, state.opacity());

    if (state.isMatrixDirty())
        program()->setUniformValue(m_id_matrix, state.combinedMatrix());

    program()->setUniformValue(m_id_texMatrix, mat->m_texMatrix);
}

StreamVideoMaterial::StreamVideoMaterial(QSGTexture *texture, TextureTarget target)
    : m_texture(texture)
    , m_target(target)
{
}

QSGMaterialShader *StreamVideoMaterial::createShader() const
{
    return new StreamVideoMaterialShader(m_target);
}

StreamVideoNode::StreamVideoNode(QSGTexture *texture, bool flip, TextureTarget target)
    : m_geometry(QSGGeometry::defaultAttributes_TexturedPoint2D(), 4)
    , m_flip(flip)
{
    setGeometry(&m_geometry);
    setFlag(QSGNode::OwnsMaterial);
    m_material = new StreamVideoMaterial(texture, target);
    setMaterial(m_material);
}

void StreamVideoNode::setRect(const QRectF &rect)
{
    if (m_flip)
        QSGGeometry::updateTexturedRectGeometry(geometry(), rect, QRectF(0, 1, 1, -1));
    else
        QSGGeometry::updateTexturedRectGeometry(geometry(), rect, QRectF(0, 0, 1, 1));
}

void StreamVideoNode::setTextureMatrix(const QMatrix4x4 &matrix)
{
    m_material->m_texMatrix = matrix;
}

} // namespace