RenderCore

Src/RenderCore/imp/cpp/TextureAtlas.cpp

@@ -0,0 +1,82 @@
+// IAEngine: 2D Game Engine by IA
+// Copyright (C) 2025 IASoft (PVT) LTD (oss@iasoft.dev)
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+#include <RenderCore/TextureAtlas.hpp>
+
+namespace ia::iae
+{
+    RDC_TextureAtlas::RDC_TextureAtlas(IN CONST Vector<Handle> &images)
+    {
+        if (images.empty())
+            return;
+
+        m_atlasSize.x = 0;
+        m_atlasSize.y = 0;
+        for (const auto &_image : images)
+        {
+            const auto d = (ImageData *) _image;
+            m_atlasSize.x += d->Width;
+            if (d->Height > m_atlasSize.y)
+                m_atlasSize.y = d->Height;
+        }
+
+        m_inverseAtlasSize = {1.0f / ((FLOAT32) m_atlasSize.x), 1.0f / ((FLOAT32) m_atlasSize.y)};
+
+        const auto pixels = new UINT8[m_atlasSize.x * m_atlasSize.y * 4];
+
+        INT32 atlasCursor{0};
+        for (const auto &_image : images)
+        {
+            const auto d = (ImageData *) _image;
+            for (INT32 y = 0; y < d->Height; y++)
+                ia_memcpy(&pixels[(atlasCursor + (y * m_atlasSize.x)) * 4], &d->Pixels[y * d->Width * 4], d->Width * 4);
+            m_texCoordMap[_image] = Vec2(((FLOAT32) atlasCursor) / ((FLOAT32) m_atlasSize.x), 0.0f);
+            atlasCursor += d->Width;
+        }
+
+        m_texture = new RDC_Texture(RDC_Texture::EType::SAMPLED, m_atlasSize.x, m_atlasSize.y);
+        m_texture->SetImageData(pixels);
+
+        delete[] pixels;
+    }
+
+    RDC_TextureAtlas::~RDC_TextureAtlas()
+    {
+        delete m_texture;
+    }
+
+    Vec4 RDC_TextureAtlas::GetTextureCoordinates(IN Handle _image, IN INT32 tileIndexX, IN INT32 tileIndexY, IN BOOL flipH,
+                                             IN BOOL flipV, IN Vec2 uvOffset)
+    {
+        const auto d = (ImageData *) _image;
+        const auto &t = m_texCoordMap[_image];
+        const auto pX = ((tileIndexX + uvOffset.x) * ((FLOAT32) d->TileWidth)) * m_inverseAtlasSize.x;
+        const auto pY = ((tileIndexY + uvOffset.y) * ((FLOAT32) d->TileHeight)) * m_inverseAtlasSize.y;
+        auto texCoords = Vec4(t.x + pX, t.y + pY, d->TileWidth * m_inverseAtlasSize.x,
+                              d->TileHeight * m_inverseAtlasSize.y);
+        if (flipH)
+        {
+            texCoords.x += texCoords.z;
+            texCoords.z *= -1;
+        }
+        if (flipV)
+        {
+            texCoords.y += texCoords.w;
+            texCoords.w *= -1;
+        }
+        return texCoords;
+    }
+} // namespace ia::iae