GLRGBScaler.cc

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#include "GLRGBScaler.hh"
#include "RenderSettings.hh"
#include "narrow.hh"
 
namespace openmsx {
 
GLRGBScaler::GLRGBScaler(
                RenderSettings& renderSettings_, GLScaler& fallback_)
        : GLScaler("rgb")
        , renderSettings(renderSettings_)
        , fallback(fallback_)
{
        for (auto i : xrange(2)) {
                program[i].activate();
                unifCnsts[i] = program[i].getUniformLocation("cnsts");
        }
}
 
void GLRGBScaler::scaleImage(
        gl::ColorTexture& src, gl::ColorTexture* superImpose,
        unsigned srcStartY, unsigned srcEndY, unsigned srcWidth,
        unsigned dstStartY, unsigned dstEndY, unsigned dstWidth,
        unsigned logSrcHeight)
{
        int i = superImpose ? 1 : 0;
 
        GLfloat blur = narrow<float>(renderSettings.getBlurFactor()) * (1.0f / 256.0f);
        GLfloat scanline = narrow<float>(renderSettings.getScanlineFactor()) * (1.0f / 255.0f);
        unsigned yScale = (dstEndY - dstStartY) / (srcEndY - srcStartY);
        if (yScale == 0) {
                // less lines in destination than in source
                // (factor=1 / interlace) --> disable scanlines
                scanline = 1.0f;
                yScale = 1;
        }
        if ((blur != 0.0f) || (scanline != 1.0f) || superImpose) {
                setup(superImpose != nullptr);
                if (srcWidth != 1) {
                        // workaround for ATI cards
                        src.setInterpolation(true);
                } else {
                        // treat border as 256-pixel wide display area
                        srcWidth = 320;
                }
                auto yScaleF = narrow<float>(yScale);
                GLfloat a = (yScale & 1) ? 0.5f : ((yScaleF + 1.0f) / (2.0f * yScaleF));
                GLfloat c1 = blur;
                GLfloat c2 = 3.0f - 2.0f * c1;
                glUniform4f(unifCnsts[i],
                            a,                             // scan_a
                            (1.0f - scanline) * 2.0f * c2, // scan_b_c2
                            scanline * c2,                 // scan_c_c2
                            (c1 - c2) / c2);               // scan_c1_2_2
                execute(src, superImpose,
                        srcStartY, srcEndY, srcWidth,
                        dstStartY, dstEndY, dstWidth,
                        logSrcHeight);
                src.setInterpolation(false);
        } else {
                fallback.scaleImage(src, superImpose,
                                    srcStartY, srcEndY, srcWidth,
                                    dstStartY, dstEndY, dstWidth,
                                    logSrcHeight);
        }
}
 
} // namespace openmsx