GLSimpleScaler.cc

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#include "GLSimpleScaler.hh"
#include "GLUtil.hh"
#include "RenderSettings.hh"
#include "memory.hh"

using std::string;

namespace openmsx {

GLSimpleScaler::GLSimpleScaler(RenderSettings& renderSettings_)
        : renderSettings(renderSettings_)
{
        for (int i = 0; i < 2; ++i) {
                Data& d = data[i];

                string header = string("#define SUPERIMPOSE ")
                              + char('0' + i) + '\n';
                VertexShader   vertexShader  (header, "simple.vert");
                FragmentShader fragmentShader(header, "simple.frag");
                d.scalerProgram.attach(vertexShader);
                d.scalerProgram.attach(fragmentShader);
                d.scalerProgram.link();
#ifdef GL_VERSION_2_0
                if (GLEW_VERSION_2_0) {
                        data[i].scalerProgram.activate();
                        GLint texLoc = d.scalerProgram.getUniformLocation("tex");
                        glUniform1i(texLoc, 0);
                        if (i == 1) {
                                GLint texLoc2 = d.scalerProgram.getUniformLocation("videoTex");
                                glUniform1i(texLoc2, 1);
                        }
                        data[i].texSizeLoc  = d.scalerProgram.getUniformLocation("texSize");
                        data[i].texStepXLoc = d.scalerProgram.getUniformLocation("texStepX");
                        data[i].cnstLoc     = d.scalerProgram.getUniformLocation("cnst");
                }
#endif
        }
}

void GLSimpleScaler::scaleImage(
        ColorTexture& src, ColorTexture* superImpose,
        unsigned srcStartY, unsigned srcEndY, unsigned srcWidth,
        unsigned dstStartY, unsigned dstEndY, unsigned dstWidth,
        unsigned logSrcHeight)
{
        Data& d = data[superImpose ? 1 : 0];

        GLfloat blur = renderSettings.getBlurFactor() / 256.0f;
        GLfloat scanline = renderSettings.getScanlineFactor() / 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) && (srcWidth != 1)) { // srcWidth check: workaround for ATI cards
                src.enableInterpolation();
        }
        if (GLEW_VERSION_2_0 && ((blur != 0.0f) || (scanline != 1.0f) || superImpose)) {
                if (superImpose) {
                        glActiveTexture(GL_TEXTURE1);
                        superImpose->bind();
                        glActiveTexture(GL_TEXTURE0);
                }
                d.scalerProgram.activate();
                GLfloat scan_a = (yScale & 1) ? 0.5f : ((yScale + 1) / (2.0f * yScale));
                GLfloat scan_b = 2.0f - 2.0f * scanline;
                GLfloat scan_c = scanline;
                if (!superImpose) {
                        // small optimization in simple.frag:
                        // divide by 2 here instead of on every pixel
                        scan_b *= 0.5f;
                        scan_c *= 0.5f;
                }
                glUniform2f(d.texSizeLoc, srcWidth, src.getHeight());
                glUniform3f(d.texStepXLoc, 1.0f / srcWidth, 1.0f / srcWidth, 0.0f);
                glUniform4f(d.cnstLoc, scan_a, scan_b, scan_c, blur);
        }

        // actually draw texture
        drawMultiTex(src, srcStartY, srcEndY, src.getHeight(), logSrcHeight,
                     dstStartY, dstEndY, dstWidth);
        src.disableInterpolation();
}

} // namespace openmsx