From 79d255b63fc8c87dc0615319f8d81eea795e4fdb Mon Sep 17 00:00:00 2001
From: Gary Talent <gary@drinkingtea.net>
Date: Sun, 11 Dec 2022 08:38:38 -0600
Subject: [PATCH] [nostalgia/core/userland] Make palettes swappable in GL
 renderer

---
 src/nostalgia/core/userland/gfx.cpp        | 10 ++++++----
 src/nostalgia/core/userland/gfx.hpp        |  6 ++++++
 src/nostalgia/core/userland/gfx_opengl.cpp | 19 +++++++++++++++++--
 3 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/src/nostalgia/core/userland/gfx.cpp b/src/nostalgia/core/userland/gfx.cpp
index e75d87dd..84ca2600 100644
--- a/src/nostalgia/core/userland/gfx.cpp
+++ b/src/nostalgia/core/userland/gfx.cpp
@@ -38,16 +38,18 @@ ox::Error loadBgTileSheet(Context *ctx,
 	if (bytesPerTile == 64) { // 8 BPP
 		pixels.resize(tilesheet->pixels.size());
 		for (std::size_t i = 0; i < tilesheet->pixels.size(); ++i) {
-			pixels[i] = toColor32(palette->colors[tilesheet->pixels[i]]);
+			pixels[i] = tilesheet->pixels[i];
 		}
 	} else { // 4 BPP
 		pixels.resize(tilesheet->pixels.size() * 2);
 		for (std::size_t i = 0; i < tilesheet->pixels.size(); ++i) {
-			pixels[i * 2 + 0] = toColor32(palette->colors[tilesheet->pixels[i] & 0xF]);
-			pixels[i * 2 + 1] = toColor32(palette->colors[tilesheet->pixels[i] >> 4]);
+			pixels[i * 2 + 0] = tilesheet->pixels[i] & 0xF;
+			pixels[i * 2 + 1] = tilesheet->pixels[i] >> 4;
 		}
 	}
-	renderer::loadBgTexture(ctx->rendererData<void>(), cbb, pixels.data(), width, height);
+	const auto rd = ctx->rendererData<void>();
+	renderer::loadBgTexture(rd, cbb, pixels.data(), width, height);
+	renderer::loadBgPalette(rd, *palette);
 	return OxError(0);
 }
 
diff --git a/src/nostalgia/core/userland/gfx.hpp b/src/nostalgia/core/userland/gfx.hpp
index 6e3831c1..92925f5f 100644
--- a/src/nostalgia/core/userland/gfx.hpp
+++ b/src/nostalgia/core/userland/gfx.hpp
@@ -8,12 +8,18 @@
 
 #include <nostalgia/core/context.hpp>
 
+namespace {
+class Palette;
+}
+
 namespace nostalgia::core::renderer {
 
 ox::Error init(Context *ctx, void **rendererData) noexcept;
 
 void shutdown(Context *ctx, void *rendererData) noexcept;
 
+void loadBgPalette(void *rendererData, const Palette &pal) noexcept;
+
 void loadBgTexture(void *rendererData, unsigned cbb, void *pixels, int w, int h) noexcept;
 
 }
diff --git a/src/nostalgia/core/userland/gfx_opengl.cpp b/src/nostalgia/core/userland/gfx_opengl.cpp
index 36f26a8f..b4db9534 100644
--- a/src/nostalgia/core/userland/gfx_opengl.cpp
+++ b/src/nostalgia/core/userland/gfx_opengl.cpp
@@ -47,6 +47,8 @@ struct GlImplData {
 	uint64_t draws = 0;
 	ox::Array<CBB, 4> cbbs;
 	ox::Array<Background, 4> backgrounds;
+	static constexpr std::size_t ColorCnt = 256;
+	ox::Array<GLfloat, ColorCnt * 3> palette{};
 };
 
 constexpr const GLchar *bgvshad = R"(
@@ -65,9 +67,11 @@ constexpr const GLchar *bgfshad = R"(
 	out vec4 outColor;
 	in vec2 fTexCoord;
 	uniform sampler2D image;
+	uniform vec3 fPalette[256];
 	void main() {
-	    //outColor = vec4(0.0, 0.7, 1.0, 1.0);
-	    outColor = texture(image, fTexCoord);
+		int idx = int(texture(image, fTexCoord).rgb.r * 256);
+		outColor = vec4(fPalette[idx], 1.0);
+		//outColor = vec4(0.0, 0.7, 1.0, 1.0);
 	})";
 
 [[nodiscard]]
@@ -175,7 +179,9 @@ static void drawBackground(CBB *cbb) noexcept {
 static void drawBackgrounds(GlImplData *id) noexcept {
 	// load background shader and its uniforms
 	glUseProgram(id->bgShader);
+	const auto uniformPalette = static_cast<GLint>(glGetUniformLocation(id->bgShader, "fPalette"));
 	const auto uniformTileHeight = static_cast<GLint>(glGetUniformLocation(id->bgShader, "vTileHeight"));
+	glUniform3fv(uniformPalette, GlImplData::ColorCnt, id->palette.data());
 	for (auto &bg : id->backgrounds) {
 		if (bg.enabled) {
 			auto &cbb = id->cbbs[bg.cbbIdx];
@@ -205,6 +211,15 @@ void shutdown(Context*, void *rendererData) noexcept {
 	ox::safeDelete(id);
 }
 
+void loadBgPalette(void *rendererData, const Palette &pal) noexcept {
+	const auto id = static_cast<GlImplData*>(rendererData);
+	for (auto i = 0u; const auto c : pal.colors) {
+		id->palette[i++] = redf(c);
+		id->palette[i++] = greenf(c);
+		id->palette[i++] = bluef(c);
+	}
+}
+
 void loadBgTexture(void *rendererData, unsigned cbbIdx, void *pixels, int w, int h) noexcept {
 	oxTracef("nostalgia::core::gfx::gl", "loadBgTexture: { cbbIdx: {}, w: {}, h: {} }", cbbIdx, w, h);
 	const auto id = static_cast<GlImplData*>(rendererData);