add palette texture coloring to hexgrid

src/scene_loader.cpp

@@ -27,8 +27,8 @@ glm::vec4 parseVec4(const rapidjson::Value& node);
 uint32 parseHex32(std::string s);
 bool validateScene(rapidjson::Document* schema_doc, rapidjson::Document* scene_doc,
 		const char* scene_file);
-void populateFilledHexBuffer(hexgrid& hg, render_group* rg_filled);
-void populateLineBuffer(hexgrid& hg, render_group* rg_lines);
+void populateFilledHexGLBuffers(hexgrid& hg, render_group* rg_filled, util_image palette_image);
+void populateLineGLBuffers(hexgrid& hg, render_group* rg_lines, util_image palette_image);
 
 
 // interface
@@ -163,18 +163,26 @@ slCreateHexRenderGroups(hexgrid& hg, render_state* rs)
 		return false;
 	}
 
-	populateFilledHexBuffer(hg, rg_filled);
-	populateLineBuffer(hg, rg_lines);
+	populateFilledHexGLBuffers(hg, rg_filled, rs->palette_image);
+	populateLineGLBuffers(hg, rg_lines, rs->palette_image);
 
 	render_object* ro = rg_filled->render_objects[0];
+	ro->use_texture = true;
+	ro->tex_id = rs->palette_id;
+
 	rgBufferData(&ro->vertex_buffer, GL_DYNAMIC_DRAW, GL_ARRAY_BUFFER);
 	rgBufferData(&ro->normal_buffer, GL_STATIC_DRAW, GL_ARRAY_BUFFER);
 	rgBufferData(&ro->color_buffer, GL_DYNAMIC_DRAW, GL_ARRAY_BUFFER);
+	rgBufferData(&ro->uv_buffer, GL_DYNAMIC_DRAW, GL_ARRAY_BUFFER);
 
 	ro = rg_lines->render_objects[0];
+	ro->use_texture = true;
+	ro->tex_id = rs->palette_id;
+
 	rgBufferData(&ro->vertex_buffer, GL_DYNAMIC_DRAW, GL_ARRAY_BUFFER);
 	rgBufferData(&ro->normal_buffer, GL_STATIC_DRAW, GL_ARRAY_BUFFER);
 	rgBufferData(&ro->color_buffer, GL_DYNAMIC_DRAW, GL_ARRAY_BUFFER);
+	rgBufferData(&ro->uv_buffer, GL_DYNAMIC_DRAW, GL_ARRAY_BUFFER);
 
 	return true;
 }
@@ -274,15 +282,25 @@ parseVec4(const rapidjson::Value& node)
 }
 
 void
-populateFilledHexBuffer(hexgrid& hg, render_group* rg_filled)
+populateFilledHexGLBuffers(hexgrid& hg, render_group* rg_filled, util_image palette_image)
 {
 	render_object* ro = rg_filled->render_objects[0];
 	gl_buffer& vbuf = ro->vertex_buffer;
 	gl_buffer& cbuf = ro->color_buffer;
 	gl_buffer& normal_buf = ro->normal_buffer;
+	gl_buffer& uv_buf = ro->uv_buffer;
 
 	assert((hg.hex_array->size() * 6 * 3 * 3) == vbuf.buffer_len);
 
+	// fill uv_buffer with palette texture coords
+	v2f fill_color_coords = utilGetPaletteCoords(palette_image, hg.fill_color);
+
+	for (uint i = 0; i < uv_buf.buffer_len; i += 3) {
+		uv_buf.buffer[i + 0] = fill_color_coords.x;
+		uv_buf.buffer[i + 1] = fill_color_coords.y;
+		uv_buf.buffer[i + 2] = 0;
+	}
+
 	hgUpdateColorBuffer(cbuf, hg.hex_array);
 
 	// cheat at vertex normals since all hexes lay flat on z-axis
@@ -333,12 +351,13 @@ populateFilledHexBuffer(hexgrid& hg, render_group* rg_filled)
 }
 
 void
-populateLineBuffer(hexgrid& hg, render_group* rg_lines)
+populateLineGLBuffers(hexgrid& hg, render_group* rg_lines, util_image palette_image)
 {
 	render_object* ro = rg_lines->render_objects[0];
 	gl_buffer& vbuf = ro->vertex_buffer;
 	gl_buffer& cbuf = ro->color_buffer;
 	gl_buffer& normal_buf = ro->normal_buffer;
+	gl_buffer& uv_buf = ro->uv_buffer;
 
 	assert((hg.hex_array->size() * 6 * 2 * 3) == vbuf.buffer_len);
 
@@ -353,6 +372,15 @@ populateLineBuffer(hexgrid& hg, render_group* rg_lines)
 		normal_buf.buffer[i + 2] = 1.f;
 	}
 
+	// fill uv_buffer with palette texture coords
+	v2f uv_coords = utilGetPaletteCoords(palette_image, hg.hex_line_color);
+
+	for (uint i = 0; i < uv_buf.buffer_len; i += 3) {
+		uv_buf.buffer[i + 0] = uv_coords.x;
+		uv_buf.buffer[i + 1] = uv_coords.y;
+		uv_buf.buffer[i + 2] = 0;
+	}
+
 	Point p1, p2;
 	int idx = 0;
 	for (int i = 0; i < (int) hg.hex_array->size(); i++)

src/util.cpp

@@ -1,5 +1,6 @@
 
 #include <cassert>
+#include <cmath>
 #include <cstdlib>
 #include <cstdio>
 #include <cstring>
@@ -120,25 +121,36 @@ utilFreeImage(util_image image)
 }
 
 // need to init default values from scene file, or finally make default config?
-util_RGBA
-renGetPaletteColor(util_image& palette_image, uint color_index)
+v2f
+utilGetPaletteCoords(util_image& palette_image, uint color_index)
 {
-	util_RGBA color;
+	v2i tex_coords;
+	v2f normalized;
 
 	if (PALETTE_ROWS * PALETTE_COLUMNS < color_index) {
 		LOG(ERROR) << "index out of range\n";
-		return color;
+		return normalized;
 	}
 
 	if (palette_image.pixels == nullptr) {
 		LOG(ERROR) << "palatte image not loaded\n";
-		return color;
+		return normalized;
 	}
 
-	// get start of pixel (remember to account for palette border)
-	// read num_channels bytes
-	// pad extra 0xFF byte if 3 channels
-	// convert 4 uint8 bytes to normalized RGBA floats
-
-	return color;
+	// NOTE: we're aiming to sample near the middle of the palette 'square' so GL_NEAREST
+	//		doesn't try to sample the border color
+	v2i palette_square;
+	palette_square.x = palette_image.w / PALETTE_ROWS;
+	palette_square.y = palette_image.h / PALETTE_COLUMNS;
+	uint v_row = (uint) std::floor(color_index / PALETTE_ROWS);
+	uint u_column = color_index % PALETTE_ROWS;
+	tex_coords.x = u_column * palette_square.x + palette_square.x / 2;
+	tex_coords.y = v_row * palette_square.y + palette_square.y / 2;
+	// NOTE: flip y coord
+	tex_coords.y = palette_image.h - tex_coords.y;
+
+	normalized.x = (float) tex_coords.x / palette_image.w;
+	normalized.y = (float) tex_coords.y / palette_image.h;
+
+	return normalized;
 }

src/util.h

@@ -108,4 +108,4 @@ util_image utilLoadImage(const char* base_dir, const char* filename);
 
 void utilFreeImage(util_image image);
 
-util_RGBA utilGetPaletteColor(util_image& palette_image, uint color_index);
+v2f utilGetPaletteCoords(util_image& palette_image, uint color_index);