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Reduced precision of input phase, but I'm not necessarily persuaded by it as a move. However it's clear that something is off in that whole area. But if phase is locked by output position, do I need to retain this level of complexity? Also ensured that intermediate buffers prior to the final are sampled using the nearest sampling mode, also to reduce precision errors.

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This commit is contained in:
Thomas Harte 2017-01-10 22:08:07 -05:00
parent eeb646868b
commit 4c3669f210
5 changed files with 26 additions and 93 deletions
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2
Outputs/CRT/CRT.cpp
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@ -147,7 +147,7 @@ void CRT::advance_cycles(unsigned int number_of_cycles, bool hsync_requested, bo
{
// output_y and texture locations will be written later; we won't necessarily know what it is outside of the locked region
source_output_position_x1() = (uint16_t)horizontal_flywheel_->get_current_output_position();
source_phase() = colour_burst_phase_;
source_phase() = 31 + colour_burst_phase_ & ~63; // phase is rounded to the nearest 1/4 of a cycle
source_amplitude() = colour_burst_amplitude_;
source_phase_time() = (uint8_t)colour_burst_time_; // assumption: burst was within the first 1/16 of the line
}

9
Outputs/CRT/Internals/CRTOpenGL.cpp
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@ -69,9 +69,9 @@ OpenGLOutputBuilder::OpenGLOutputBuilder(size_t bytes_per_pixel) :
// }
// else
{
composite_texture_.reset(new OpenGL::TextureTarget(IntermediateBufferWidth, IntermediateBufferHeight, composite_texture_unit));
separated_texture_.reset(new OpenGL::TextureTarget(IntermediateBufferWidth, IntermediateBufferHeight, separated_texture_unit));
filtered_texture_.reset(new OpenGL::TextureTarget(IntermediateBufferWidth, IntermediateBufferHeight, filtered_texture_unit));
composite_texture_.reset(new OpenGL::TextureTarget(IntermediateBufferWidth, IntermediateBufferHeight, composite_texture_unit, GL_NEAREST));
separated_texture_.reset(new OpenGL::TextureTarget(IntermediateBufferWidth, IntermediateBufferHeight, separated_texture_unit, GL_NEAREST));
filtered_texture_.reset(new OpenGL::TextureTarget(IntermediateBufferWidth, IntermediateBufferHeight, filtered_texture_unit, GL_LINEAR));
}
}
@ -117,7 +117,7 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
// make sure there's a target to draw to
if(!framebuffer_ || framebuffer_->get_height() != output_height || framebuffer_->get_width() != output_width)
{
std::unique_ptr<OpenGL::TextureTarget> new_framebuffer(new OpenGL::TextureTarget((GLsizei)output_width, (GLsizei)output_height, pixel_accumulation_texture_unit));
std::unique_ptr<OpenGL::TextureTarget> new_framebuffer(new OpenGL::TextureTarget((GLsizei)output_width, (GLsizei)output_height, pixel_accumulation_texture_unit, GL_LINEAR));
if(framebuffer_)
{
new_framebuffer->bind_framebuffer();
@ -346,6 +346,7 @@ void OpenGLOutputBuilder::prepare_output_shader()
{
output_shader_program_ = OpenGL::OutputShader::make_shader("", "texture(texID, srcCoordinatesVarying).rgb", false);
output_shader_program_->set_source_texture_unit(work_texture_ ? work_texture_unit : filtered_texture_unit);
// output_shader_program_->set_source_texture_unit(composite_texture_unit);
output_shader_program_->set_origin_is_double_height(!!work_texture_);
}

102
Outputs/CRT/Internals/Shaders/IntermediateShader.cpp
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@ -75,7 +75,7 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_shader(const char *
// keep iInputPositionVarying in whole source pixels, scale mappedInputPosition to the ordinary normalised range
"vec2 textureSize = vec2(textureSize(texID, 0));"
"iInputPositionVarying = extendedInputPosition;"
"vec2 mappedInputPosition = (extendedInputPosition + vec2(0.0, 0.5)) / textureSize;"
"vec2 mappedInputPosition = (extendedInputPosition) / textureSize;" // + vec2(0.0, 0.5)
// setup input positions spaced as per the supplied offsets; these are for filtering where required
"inputPositionsVarying[0] = mappedInputPosition - (vec2(5.0, 0.0) / textureSize);"
@ -93,7 +93,8 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_shader(const char *
// setup phaseAndAmplitudeVarying.x as colour burst subcarrier phase, in radians;
// setup phaseAndAmplitudeVarying.x as colour burst amplitude
"phaseAndAmplitudeVarying.x = (((extendedOutputPosition.x - phaseTimeAndAmplitude.y) / 4.0) + (phaseTimeAndAmplitude.x / 255.0)) * 2.0 * 3.141592654;"
"phaseAndAmplitudeVarying.x = (extendedOutputPosition.x - phaseTimeAndAmplitude.y*widthScalers[1]) / 4.0 + phaseTimeAndAmplitude.x / 255.0;"
"phaseAndAmplitudeVarying.x *= 2.0 * 3.141592654;"
"phaseAndAmplitudeVarying.y = 0.33;" // TODO: reinstate connection with (phaseTimeAndAmplitude.y/256.0)
// determine output position by scaling the output position according to the texture size
@ -187,7 +188,6 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_chroma_luma_separat
"in vec2 phaseAndAmplitudeVarying;"
"in vec2 inputPositionsVarying[11];"
"uniform vec4 weights[3];"
"out vec3 fragColour;"
@ -195,54 +195,16 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_chroma_luma_separat
"void main(void)"
"{"
// grab 11 samples
"vec3 samples[] = vec3[]("
"vec3("
"texture(texID, inputPositionsVarying[0]).r,"
"texture(texID, inputPositionsVarying[2]).r,"
"texture(texID, inputPositionsVarying[3]).r"
"),"
"vec3("
"texture(texID, inputPositionsVarying[4]).r,"
"texture(texID, inputPositionsVarying[5]).r,"
"texture(texID, inputPositionsVarying[6]).r"
"),"
"vec3("
"texture(texID, inputPositionsVarying[7]).r,"
"texture(texID, inputPositionsVarying[8]).r,"
"texture(texID, inputPositionsVarying[10]).r"
")"
"vec4 samples = vec4("
"texture(texID, inputPositionsVarying[3]).r,"
"texture(texID, inputPositionsVarying[4]).r,"
"texture(texID, inputPositionsVarying[5]).r,"
"texture(texID, inputPositionsVarying[6]).r"
");"
"vec3 fixedWeights[] = vec3[]("
"vec3("
"-0.000918,"
"0.027278,"
"0.103969"
"),"
"vec3("
"0.202962,"
"0.250000,"
"0.202962"
"),"
"vec3("
"0.103969,"
"0.027278,"
"-0.000918"
")"
");"
// apply the low-pass filter to separate luma
"float luminance = "
"dot(vec3("
"dot(samples[0], fixedWeights[0]),"
"dot(samples[1], fixedWeights[1]),"
"dot(samples[2], fixedWeights[2])"
"), vec3(1.0));"
"float luminance = dot(samples, vec4(0.25));"
// define chroma to be whatever was here, minus luma
"float chrominance = 0.5 * (samples[1].y - luminance) / phaseAndAmplitudeVarying.y;"
"float chrominance = 0.5 * (samples.z - luminance) / phaseAndAmplitudeVarying.y;"
"luminance /= (1.0 - phaseAndAmplitudeVarying.y);"
// split choma colours here, as the most direct place, writing out
@ -268,48 +230,18 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_chroma_filter_shade
"void main(void)"
"{"
"vec3 samples[] = vec3[]("
"texture(texID, inputPositionsVarying[0]).rgb,"
"texture(texID, inputPositionsVarying[2]).rgb,"
"texture(texID, inputPositionsVarying[3]).rgb,"
"texture(texID, inputPositionsVarying[4]).rgb,"
"texture(texID, inputPositionsVarying[5]).rgb,"
"texture(texID, inputPositionsVarying[6]).rgb,"
"texture(texID, inputPositionsVarying[8]).rgb,"
"texture(texID, inputPositionsVarying[10]).rgb"
"texture(texID, inputPositionsVarying[6]).rgb"
");"
"vec4 fixedWeights[2] = vec4[]("
"vec4("
"0.001298,"
"-0.038576,"
"0.287031,"
"0.500000"
"),"
"vec4("
"0.287031,"
"-0.038576,"
"0.001298,"
"0.0"
")"
");"
"vec4 chromaChannel1 = vec4(samples[0].g, samples[1].g, samples[2].g, samples[3].g);"
"vec4 chromaChannel2 = vec4(samples[0].b, samples[1].b, samples[2].b, samples[3].b);"
"vec4 chromaChannel1[] = vec4[]("
"vec4(samples[0].g, samples[1].g, samples[2].g, samples[3].g),"
"vec4(samples[4].g, samples[5].g, samples[6].g, 0.0)"
");"
"vec4 chromaChannel2[] = vec4[]("
"vec4(samples[0].b, samples[1].b, samples[2].b, samples[3].b),"
"vec4(samples[4].b, samples[5].b, samples[6].b, 0.0)"
");"
"vec3 lumaChromaColour = vec3(samples[3].r,"
"dot(vec2("
"dot(chromaChannel1[0], fixedWeights[0]),"
"dot(chromaChannel1[1], fixedWeights[1])"
"), vec2(1.0)),"
"dot(vec2("
"dot(chromaChannel2[0], fixedWeights[0]),"
"dot(chromaChannel2[1], fixedWeights[1])"
"), vec2(1.0))"
"vec3 lumaChromaColour = vec3(samples[2].r,"
"dot(chromaChannel1, vec4(0.25)),"
"dot(chromaChannel2, vec4(0.25))"
");"
"vec3 lumaChromaColourInRange = (lumaChromaColour - vec3(0.0, 0.5, 0.5)) * vec3(1.0, 2.0, 2.0);"

4
Outputs/CRT/Internals/TextureTarget.cpp
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@ -12,7 +12,7 @@
using namespace OpenGL;
TextureTarget::TextureTarget(GLsizei width, GLsizei height, GLenum texture_unit) :
TextureTarget::TextureTarget(GLsizei width, GLsizei height, GLenum texture_unit, GLint mag_filter) :
_width(width),
_height(height),
_pixel_shader(nullptr),
@ -33,7 +33,7 @@ TextureTarget::TextureTarget(GLsizei width, GLsizei height, GLenum texture_unit)
uint8_t *blank_buffer = (uint8_t *)calloc((size_t)(_expanded_width * _expanded_height), 4);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, (GLsizei)_expanded_width, (GLsizei)_expanded_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, blank_buffer);
free(blank_buffer);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, mag_filter);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, _texture, 0);

2
Outputs/CRT/Internals/TextureTarget.hpp
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@ -30,7 +30,7 @@ class TextureTarget {
@param height The height of target to create.
@param texture_unit A texture unit on which to bind the texture.
*/
TextureTarget(GLsizei width, GLsizei height, GLenum texture_unit);
TextureTarget(GLsizei width, GLsizei height, GLenum texture_unit, GLint mag_filter);
~TextureTarget();
/*!