From b2dad28fa03e3eb376b993fed6bee63725bd11eb Mon Sep 17 00:00:00 2001
From: Kai Blaschke <kai.blaschke@kb-dev.net>
Date: Wed, 1 Nov 2023 22:07:02 +0100
Subject: [PATCH] Pack transition shaders into a resource header.

Also added a "sweep" transition.
---
 .../BuiltInTransitionsResources.hpp.in        |  5 +++
 src/libprojectM/Renderer/CMakeLists.txt       | 31 +++++++++++++++++++
 .../GenerateBuiltInTransitionsResources.cmake | 19 ++++++++++++
 ...sitionShaderBuiltInSimpleBlendGlsl330.frag |  2 +-
 .../TransitionShaderBuiltInSweepGlsl330.frag  | 22 +++++++++++++
 5 files changed, 78 insertions(+), 1 deletion(-)
 create mode 100644 src/libprojectM/Renderer/BuiltInTransitionsResources.hpp.in
 create mode 100644 src/libprojectM/Renderer/GenerateBuiltInTransitionsResources.cmake
 create mode 100644 src/libprojectM/Renderer/TransitionShaders/TransitionShaderBuiltInSweepGlsl330.frag

diff --git a/src/libprojectM/Renderer/BuiltInTransitionsResources.hpp.in b/src/libprojectM/Renderer/BuiltInTransitionsResources.hpp.in
new file mode 100644
index 000000000..0097f66d9
--- /dev/null
+++ b/src/libprojectM/Renderer/BuiltInTransitionsResources.hpp.in
@@ -0,0 +1,5 @@
+#pragma once
+
+#include <string>
+
+@STATIC_SHADER_CONTENTS@
diff --git a/src/libprojectM/Renderer/CMakeLists.txt b/src/libprojectM/Renderer/CMakeLists.txt
index ad7f45217..35b94b1e5 100644
--- a/src/libprojectM/Renderer/CMakeLists.txt
+++ b/src/libprojectM/Renderer/CMakeLists.txt
@@ -1,4 +1,32 @@
+set(TRANSITION_SHADER_FILES
+        TransitionShaders/TransitionShaderBuiltInSimpleBlendGlsl330.frag
+        TransitionShaders/TransitionShaderBuiltInSweepGlsl330.frag
+        TransitionShaders/TransitionVertexShaderGlsl330.vert
+        TransitionShaders/TransitionShaderHeaderGlsl330.frag
+        TransitionShaders/TransitionShaderMainGlsl330.frag
+        )
+
+string(REPLACE ";" "\\;" TRANSITION_SHADER_FILES_ARG "${TRANSITION_SHADER_FILES}")
+add_custom_command(OUTPUT
+        ${CMAKE_CURRENT_BINARY_DIR}/BuiltInTransitionsResources.hpp
+
+        COMMAND ${CMAKE_COMMAND}
+
+        ARGS
+        -D SHADER_FILES="${TRANSITION_SHADER_FILES_ARG}"
+        -D OUTPUT_DIR=${CMAKE_CURRENT_BINARY_DIR}
+        -P ${CMAKE_CURRENT_SOURCE_DIR}/GenerateBuiltInTransitionsResources.cmake
+
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+        DEPENDS # Files watched for changes:
+        ${TRANSITION_SHADER_FILES}
+        BuiltInTransitionsResources.hpp.in
+        GenerateBuiltInTransitionsResources.cmake
+        )
+
 add_library(Renderer OBJECT
+        ${CMAKE_CURRENT_BINARY_DIR}/BuiltInTransitionsResources.hpp
+        BuiltInTransitionsResources.hpp.in
         FileScanner.cpp
         FileScanner.hpp
         Framebuffer.cpp
@@ -23,11 +51,14 @@ add_library(Renderer OBJECT
         TextureManager.hpp
         TextureSamplerDescriptor.cpp
         TextureSamplerDescriptor.hpp
+        TransitionShaderManager.cpp
+        TransitionShaderManager.hpp
         )
 
 target_include_directories(Renderer
         PRIVATE
         "${CMAKE_CURRENT_SOURCE_DIR}/.."
+        "${CMAKE_CURRENT_BINARY_DIR}"
         PUBLIC
         "${CMAKE_CURRENT_SOURCE_DIR}"
         )
diff --git a/src/libprojectM/Renderer/GenerateBuiltInTransitionsResources.cmake b/src/libprojectM/Renderer/GenerateBuiltInTransitionsResources.cmake
new file mode 100644
index 000000000..208a884d2
--- /dev/null
+++ b/src/libprojectM/Renderer/GenerateBuiltInTransitionsResources.cmake
@@ -0,0 +1,19 @@
+cmake_minimum_required(VERSION 3.20 FATAL_ERROR)
+
+# Run as custom command in script mode if any shader file has changed.
+# Recreates the BuiltInTransitionsResources.hpp file accordingly.
+
+set(STATIC_SHADER_CONTENTS "")
+foreach(shader_file IN LISTS SHADER_FILES)
+    cmake_path(GET shader_file FILENAME _shader_name)
+    cmake_path(GET shader_file EXTENSION _shader_type)
+    cmake_path(REMOVE_EXTENSION _shader_name)
+    file(READ "${shader_file}" _shader_contents)
+
+    string(REGEX REPLACE "Glsl([0-9]+)" "" _accessor_name ${_shader_name})
+
+    string(APPEND STATIC_SHADER_CONTENTS "static std::string k${_shader_name} = R\"(\n${_shader_contents})\";\n\n")
+
+endforeach()
+
+configure_file(BuiltInTransitionsResources.hpp.in ${OUTPUT_DIR}/BuiltInTransitionsResources.hpp @ONLY)
diff --git a/src/libprojectM/Renderer/TransitionShaders/TransitionShaderBuiltInSimpleBlendGlsl330.frag b/src/libprojectM/Renderer/TransitionShaders/TransitionShaderBuiltInSimpleBlendGlsl330.frag
index cdea8fcd1..97e2f1469 100644
--- a/src/libprojectM/Renderer/TransitionShaders/TransitionShaderBuiltInSimpleBlendGlsl330.frag
+++ b/src/libprojectM/Renderer/TransitionShaders/TransitionShaderBuiltInSimpleBlendGlsl330.frag
@@ -1,4 +1,4 @@
-
+// Simple crossfade effect from old to new
 void mainImage( out vec4 fragColor, in vec2 fragCoord )
 {
     vec2 uv = fragCoord / iResolution.xy;
diff --git a/src/libprojectM/Renderer/TransitionShaders/TransitionShaderBuiltInSweepGlsl330.frag b/src/libprojectM/Renderer/TransitionShaders/TransitionShaderBuiltInSweepGlsl330.frag
new file mode 100644
index 000000000..9a28625c1
--- /dev/null
+++ b/src/libprojectM/Renderer/TransitionShaders/TransitionShaderBuiltInSweepGlsl330.frag
@@ -0,0 +1,22 @@
+// Side-to-side sweep with random angle and transition zone width
+void mainImage( out vec4 fragColor, in vec2 fragCoord )
+{
+    vec2 uv = fragCoord / iResolution.xy;
+    vec3 imgOld = texture(iChannel0, uv).xyz;
+    vec3 imgNew = texture(iChannel1, uv).xyz;
+
+    // Blending
+    float currentAngle = mod(float(iRandStatic.x), 360.);
+    float blendWidth = mod(float(iRandStatic.y), .25) + .05;
+
+    uv -= .5;
+    float angle = radians(90.0) - radians(currentAngle) + atan(uv.y, uv.x);
+
+    float len = length(uv) / sqrt(2.);
+    uv = vec2(cos(angle) * len, sin(angle) * len) + .5;
+
+    vec3 col = mix(imgOld, imgNew, smoothstep(prog, prog + blendWidth, (uv.x / (1.0 + 2. * blendWidth)) + blendWidth));
+
+    // Output to screen
+    fragColor = vec4(col, 1.0);
+}