[nostalgia] Start on new TileSheetEditor

src/nostalgia/core/studio/tilesheetpixels.cpp

@@ -0,0 +1,108 @@
+/*
+ * Copyright 2016 - 2021 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#include <nostalgia/core/consts.hpp>
+#include "ptidxconv.hpp"
+#include "tilesheetpixels.hpp"
+
+namespace nostalgia::core {
+
+ox::Error TileSheetPixels::buildShader() noexcept {
+	const auto Vshad = ox::sfmt(VShad, glutils::GlslVersion);
+	const auto Fshad = ox::sfmt(FShad, glutils::GlslVersion);
+	return glutils::buildShaderProgram(Vshad, Fshad).moveTo(&m_shader);
+}
+
+void TileSheetPixels::draw(bool update) noexcept {
+	glUseProgram(m_shader);
+	glBindVertexArray(m_bufferSet.vao);
+	if (update) {
+		glutils::sendVbo(m_bufferSet);
+	}
+	glDrawElements(GL_TRIANGLES, static_cast<GLsizei>(m_bufferSet.elements.size()), GL_UNSIGNED_INT, nullptr);
+}
+
+void TileSheetPixels::initBufferSet(const NostalgiaGraphic &img, const NostalgiaPalette &pal) noexcept {
+	// vao
+	m_bufferSet.vao = glutils::generateVertexArrayObject();
+	glBindVertexArray(m_bufferSet.vao);
+	// vbo & ebo
+	m_bufferSet.vbo = glutils::generateBuffer();
+	m_bufferSet.ebo = glutils::generateBuffer();
+	setBufferObjects(img, pal, &m_bufferSet);
+	glutils::sendVbo(m_bufferSet);
+	glutils::sendEbo(m_bufferSet);
+	// vbo layout
+	const auto posAttr = static_cast<GLuint>(glGetAttribLocation(m_shader, "vPosition"));
+	glEnableVertexAttribArray(posAttr);
+	glVertexAttribPointer(posAttr, 2, GL_FLOAT, GL_FALSE, VertexVboRowLength * sizeof(float), nullptr);
+	const auto colorAttr = static_cast<GLuint>(glGetAttribLocation(m_shader, "vColor"));
+	glEnableVertexAttribArray(colorAttr);
+	glVertexAttribPointer(colorAttr, 3, GL_FLOAT, GL_FALSE, VertexVboRowLength * sizeof(float),
+	                      reinterpret_cast<void*>(2 * sizeof(float)));
+}
+
+void TileSheetPixels::setPixelBufferObject(unsigned vertexRow, float x, float y, Color16 color, float *vbo, GLuint *ebo) noexcept {
+	const auto [xmod, ymod] = pixelSize();
+	x *= xmod;
+	y *= -ymod;
+	x -= 1.0f;
+	y += 1.0f - ymod;
+	//std::cout << x << ", " << y << ", " << (x + xmod) << ", " << (y + ymod) << '\n';
+	const auto r = redf(color), g = greenf(color), b = bluef(color);
+	// don't worry, these memcpys gets optimized to something much more ideal
+	const float vertices[VertexVboLength] = {
+			       x,        y, r, g, b, // bottom left
+			x + xmod,        y, r, g, b, // bottom right
+			x + xmod, y + ymod, r, g, b, // top right
+			       x, y + ymod, r, g, b, // top left
+	};
+	memcpy(vbo, vertices, sizeof(vertices));
+	const GLuint elms[VertexEboLength] = {
+			vertexRow + 0, vertexRow + 1, vertexRow + 2,
+			vertexRow + 2, vertexRow + 3, vertexRow + 0,
+	};
+	memcpy(ebo, elms, sizeof(elms));
+}
+
+void TileSheetPixels::setBufferObjects(const NostalgiaGraphic &img, const NostalgiaPalette &pal, glutils::BufferSet *bg) noexcept {
+	const auto setPixel = [bg, img, pal](std::size_t i, uint8_t p) {
+		const auto color = pal.colors[p];
+		const auto pt = idxToPt(i, img.columns);
+		const auto fx = static_cast<float>(pt.x);
+		const auto fy = static_cast<float>(pt.y);
+		const auto vbo = &bg->vertices[i * VertexVboLength];
+		const auto ebo = &bg->elements[i * VertexEboLength];
+		setPixelBufferObject(i * VertexVboRows, fx, fy, color, vbo, ebo);
+	};
+	// set buffer lengths
+	const auto width = img.columns * TileWidth;
+	const auto height = img.rows * TileHeight;
+	const auto tiles = static_cast<unsigned>(width * height);
+	m_bufferSet.vertices.resize(tiles * VertexVboLength);
+	m_bufferSet.elements.resize(tiles * VertexEboLength);
+	// set pixels
+	if (img.bpp == 4) {
+		for (std::size_t i = 0; i < img.pixels.size(); ++i) {
+			const auto colorIdx1 = img.pixels[i] & 0xF;
+			const auto colorIdx2 = img.pixels[i] >> 4;
+			setPixel(i * 2 + 0, colorIdx1);
+			setPixel(i * 2 + 1, colorIdx2);
+		}
+	} else {
+		for (std::size_t i = 0; i < img.pixels.size(); ++i) {
+			const auto p = img.pixels[i];
+			setPixel(i, p);
+		}
+	}
+}
+
+ImVec2 TileSheetPixels::pixelSize() noexcept {
+	const auto [sw, sh] = ImGui::GetContentRegionAvail();
+	constexpr float ymod = 0.35f / 10.0f;
+	const auto xmod = ymod * sh / sw;
+	return {xmod, ymod};
+}
+
+}