6502/CLK
1
0
Fork 0
mirror of https://github.com/TomHarte/CLK.git synced 2024-08-20 13:29:27 +00:00
Code Issues Projects Releases Wiki Activity

Merge pull request #854 from TomHarte/OpenGLNoColourBurst

Browse Source 
Avoids all risk of infinities when there is no colour burst
This commit is contained in:
Thomas Harte 2020-11-28 23:54:29 -05:00 committed by GitHub
commit 9610672615
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 33 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
Outputs/OpenGL/ScanTargetGLSLFragments.cpp
View File

@ -341,7 +341,7 @@ std::unique_ptr<Shader> ScanTarget::conversion_shader() const {
vertex_shader += vertex_shader +=
"compositeAngle = (mix(startCompositeAngle, endCompositeAngle, lateral) / 32.0) * 3.141592654;" "compositeAngle = (mix(startCompositeAngle, endCompositeAngle, lateral) / 32.0) * 3.141592654;"
"compositeAmplitude = lineCompositeAmplitude / 255.0;" "compositeAmplitude = lineCompositeAmplitude / 255.0;"
"oneOverCompositeAmplitude = mix(0.0, 255.0 / lineCompositeAmplitude, step(0.01, lineCompositeAmplitude));"; "oneOverCompositeAmplitude = mix(0.0, 255.0 / lineCompositeAmplitude, step(0.95, lineCompositeAmplitude));";
} }
vertex_shader += vertex_shader +=
@ -379,40 +379,42 @@ std::unique_ptr<Shader> ScanTarget::conversion_shader() const {
switch(modals.display_type) { switch(modals.display_type) {
case DisplayType::CompositeColour: case DisplayType::CompositeColour:
fragment_shader += fragment_shader += R"x(
"vec4 angles = compositeAngle + compositeAngleOffsets;" vec4 angles = compositeAngle + compositeAngleOffsets;
// Sample four times over, at proper angle offsets. // Sample four times over, at proper angle offsets.
"vec4 samples = vec4(" vec4 samples = vec4(
"composite_sample(textureCoordinates[0], angles.x)," composite_sample(textureCoordinates[0], angles.x),
"composite_sample(textureCoordinates[1], angles.y)," composite_sample(textureCoordinates[1], angles.y),
"composite_sample(textureCoordinates[2], angles.z)," composite_sample(textureCoordinates[2], angles.z),
"composite_sample(textureCoordinates[3], angles.w)" composite_sample(textureCoordinates[3], angles.w)
");" );
// Compute a luminance for use if there's no colour information, now, before // The outer structure of the OpenGL scan target means in practice that
// modifying samples. // compositeAmplitude will be the same value across a piece of
"float mono_luminance = dot(samples, vec4(0.15, 0.35, 0.35, 0.15));" // geometry. I am therefore optimistic that this conditional will not
// cause a divergence in fragment execution.
if(compositeAmplitude < 0.01) {
// Compute only a luminance for use if there's no colour information.
fragColour3 = vec3(dot(samples, vec4(0.15, 0.35, 0.35, 0.15)));
} else {
// Take the average to calculate luminance, then subtract that from all four samples to
// give chrominance.
float luminance = dot(samples, vec4(0.25));
// Take the average to calculate luminance, then subtract that from all four samples to // Split and average chrominance.
// give chrominance. vec2 chrominances[4] = vec2[4](
"float luminance = dot(samples, vec4(0.25));" textureLod(qamTextureName, qamTextureCoordinates[0], 0).gb,
textureLod(qamTextureName, qamTextureCoordinates[1], 0).gb,
textureLod(qamTextureName, qamTextureCoordinates[2], 0).gb,
textureLod(qamTextureName, qamTextureCoordinates[3], 0).gb
);
vec2 channels = (chrominances[0] + chrominances[1] + chrominances[2] + chrominances[3])*0.5 - vec2(1.0);
// Split and average chrominance. // Apply a colour space conversion to get RGB.
"vec2 chrominances[4] = vec2[4](" fragColour3 = lumaChromaToRGB * vec3(luminance / (1.0 - compositeAmplitude), channels);
"textureLod(qamTextureName, qamTextureCoordinates[0], 0).gb," }
"textureLod(qamTextureName, qamTextureCoordinates[1], 0).gb," )x";
"textureLod(qamTextureName, qamTextureCoordinates[2], 0).gb,"
"textureLod(qamTextureName, qamTextureCoordinates[3], 0).gb"
");"
"vec2 channels = (chrominances[0] + chrominances[1] + chrominances[2] + chrominances[3])*0.5 - vec2(1.0);"
// Apply a colour space conversion to get RGB.
"fragColour3 = mix("
"lumaChromaToRGB * vec3(luminance / (1.0 - compositeAmplitude), channels),"
"vec3(mono_luminance),"
"step(oneOverCompositeAmplitude, 0.01)"
");";
break; break;
case DisplayType::CompositeMonochrome: case DisplayType::CompositeMonochrome:
@ -622,7 +624,7 @@ std::unique_ptr<Shader> ScanTarget::qam_separation_shader() const {
"compositeAngle = compositeAngle * 2.0 * 3.141592654;" "compositeAngle = compositeAngle * 2.0 * 3.141592654;"
"compositeAmplitude = lineCompositeAmplitude / 255.0;" "compositeAmplitude = lineCompositeAmplitude / 255.0;"
"oneOverCompositeAmplitude = mix(0.0, 255.0 / lineCompositeAmplitude, step(0.01, lineCompositeAmplitude));"; "oneOverCompositeAmplitude = mix(0.0, 255.0 / lineCompositeAmplitude, step(0.95, lineCompositeAmplitude));";
if(is_svideo) { if(is_svideo) {
vertex_shader += vertex_shader +=