From b46a0d9369fbaa1938f0968ab216bc2d564a9c37 Mon Sep 17 00:00:00 2001
From: fschildt <florian.schildt@protonmail.com>
Date: Mon, 21 Jul 2025 16:07:28 +0200
Subject: first commit

---
 src/renderer/RenderGroup.cpp | 94 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 src/renderer/RenderGroup.cpp

(limited to 'src/renderer/RenderGroup.cpp')

diff --git a/src/renderer/RenderGroup.cpp b/src/renderer/RenderGroup.cpp
new file mode 100644
index 0000000..56e7ec5
--- /dev/null
+++ b/src/renderer/RenderGroup.cpp
@@ -0,0 +1,94 @@
+#include <renderer/RenderGroup.hpp>
+#include <algorithm>
+
+RSortEntry::RSortEntry(float z, size_t entity_index)
+        : z(z), entity_index(entity_index) {
+}
+
+RenderGroup::RenderGroup() {
+    m_REntities.reserve(1024);
+    m_RSortEntries.reserve(1024);
+}
+
+void RenderGroup::Reset() {
+    m_CameraWidth = 0;
+    m_CameraHeight = 0;
+    m_REntities.clear();
+    m_RSortEntries.clear();
+    m_REntities.reserve(1024);
+    m_RSortEntries.reserve(1024);
+}
+
+void RenderGroup::SetCameraSize(float width, float height) {
+    m_CameraWidth = width;
+    m_CameraHeight = height;
+}
+
+float RenderGroup::GetScale() {
+    float screen_width = static_cast<float>(m_ScreenWidth);
+    float screen_height = static_cast<float>(m_ScreenHeight);
+    float xunits = screen_width / m_CameraWidth;
+    float yunits = screen_height / m_CameraHeight;
+    float scale = std::min(xunits, yunits);
+    return scale;
+}
+
+V2F32 RenderGroup::ViewPosToScreenPos(V2F32 view_pos) {
+    float scale = GetScale();
+    float screen_width = static_cast<float>(m_ScreenWidth);
+    float screen_height = static_cast<float>(m_ScreenHeight);
+    float viewport_width = m_CameraWidth * scale;
+    float viewport_height = m_CameraHeight * scale;
+    float viewport_x0 = (screen_width - viewport_width) / 2;
+    float viewport_y0 = (screen_height - viewport_height) / 2;
+
+    V2F32 result;
+    result.x = viewport_x0 + view_pos.x * scale;
+    result.y = screen_height - (viewport_y0 + view_pos.y * scale);
+
+    return result;
+}
+
+V2F32 RenderGroup::ViewSizeToScreenSize(V2F32 view_size) {
+    float scale = GetScale();
+
+    V2F32 result;
+    result.x = view_size.x * scale;
+    result.y = view_size.y * scale;
+
+    return result;
+}
+
+ImVec2 RenderGroup::ViewPosToScreenPosImGui(V2F32 view_pos) {
+    V2F32 screen_pos = ViewPosToScreenPos(view_pos);
+    ImVec2 result = {screen_pos.x, screen_pos.y};
+    return result;
+}
+
+ImVec2 RenderGroup::ViewSizeToScreenSizeImGui(V2F32 view_size) {
+    V2F32 screen_size = ViewSizeToScreenSize(view_size);
+    ImVec2 result = {screen_size.x, screen_size.y};
+    return result;
+}
+
+void RenderGroup::Clear(V3F32 color) {
+    m_ClearColor = color;
+}
+
+void RenderGroup::PushRectangle(V3F32 pos, V2F32 dim, V3F32 color) {
+    m_REntities.emplace_back(REntity{.rect{REntityType_Rectangle, pos, dim, color}});
+    m_RSortEntries.emplace_back(pos.z, m_REntities.size()-1);
+}
+
+void RenderGroup::PushBitmap(V3F32 pos, int w, int h, void *data) {
+    m_REntities.emplace_back(REntity{.bitmap{REntityType_Bitmap, pos, w, h, data}});
+    m_RSortEntries.emplace_back(pos.z, m_REntities.size()-1);
+}
+
+void RenderGroup::Sort() {
+    std::sort(m_RSortEntries.begin(), m_RSortEntries.end(),
+              [](const RSortEntry& e1, const RSortEntry& e2) {
+                  return e1.z < e2.z;
+              });
+}
+
-- 
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