Isolate legacy stroke edge shader setup

src/legacy_canvas_stroke_edge_services.h

@@ -0,0 +1,66 @@
+#pragma once
+
+#include "shader.h"
+#include "util.h"
+
+#include <functional>
+
+namespace pp::panopainter {
+
+struct LegacyStrokePadUniforms {
+    glm::vec4 color {};
+    bool uses_destination_feedback = false;
+};
+
+struct LegacyStrokeDilateUniforms {
+    glm::mat4 mvp { 1.0f };
+};
+
+struct LegacyStrokeEdgeShaderExecution {
+    std::function<void(kShader)> use_shader;
+    std::function<void(kShaderUniform, int)> set_int;
+    std::function<void(kShaderUniform, const glm::vec4&)> set_vec4;
+    std::function<void(kShaderUniform, const glm::mat4&)> set_mat4;
+};
+
+[[nodiscard]] inline LegacyStrokeEdgeShaderExecution legacy_shader_manager_stroke_edge_execution() noexcept
+{
+    return {
+        .use_shader = [](kShader shader) { ShaderManager::use(shader); },
+        .set_int = [](kShaderUniform uniform, int value) { ShaderManager::u_int(uniform, value); },
+        .set_vec4 = [](kShaderUniform uniform, const glm::vec4& value) { ShaderManager::u_vec4(uniform, value); },
+        .set_mat4 = [](kShaderUniform uniform, const glm::mat4& value) { ShaderManager::u_mat4(uniform, value); },
+    };
+}
+
+inline void setup_legacy_stroke_pad_shader(
+    const LegacyStrokePadUniforms& uniforms,
+    const LegacyStrokeEdgeShaderExecution& execution) noexcept
+{
+    execution.use_shader(kShader::StrokePad);
+    execution.set_vec4(kShaderUniform::Col, uniforms.color);
+    if (uniforms.uses_destination_feedback) {
+        execution.set_int(kShaderUniform::TexBG, 1);
+    }
+}
+
+inline void setup_legacy_stroke_pad_shader(const LegacyStrokePadUniforms& uniforms)
+{
+    setup_legacy_stroke_pad_shader(uniforms, legacy_shader_manager_stroke_edge_execution());
+}
+
+inline void setup_legacy_stroke_dilate_shader(
+    const LegacyStrokeDilateUniforms& uniforms,
+    const LegacyStrokeEdgeShaderExecution& execution) noexcept
+{
+    execution.use_shader(kShader::StrokeDilate);
+    execution.set_mat4(kShaderUniform::MVP, uniforms.mvp);
+    execution.set_int(kShaderUniform::TexBG, 0);
+}
+
+inline void setup_legacy_stroke_dilate_shader(const LegacyStrokeDilateUniforms& uniforms)
+{
+    setup_legacy_stroke_dilate_shader(uniforms, legacy_shader_manager_stroke_edge_execution());
+}
+
+} // namespace pp::panopainter