WIP PNG Image Support

kraken/resources/texture/KRTextureManager.cpp

@@ -33,6 +33,7 @@
 #include "KRTextureManager.h"
 #include "KRContext.h"
 #include "KRTexture2D.h"
+#include "KRTexturePNG.h"
 #include "KRTexturePVR.h"
 #include "KRTextureTGA.h"
 #include "KRTextureKTX.h"
@@ -107,8 +108,9 @@ KRTexture* KRTextureManager::loadTexture(const char* szName, const char* szExten
   std::transform(lowerExtension.begin(), lowerExtension.end(),
                  lowerExtension.begin(), ::tolower);
 
-
-  if (strcmp(szExtension, "pvr") == 0) {
+  if (strcmp(szExtension, "png") == 0) {
+      pTexture = new KRTexturePNG(getContext(), data, szName);
+  } else if (strcmp(szExtension, "pvr") == 0) {
     pTexture = new KRTexturePVR(getContext(), data, szName);
   } else if (strcmp(szExtension, "tga") == 0) {
     pTexture = new KRTextureTGA(getContext(), data, szName);

kraken/resources/texture/KRTexturePNG.cpp

@@ -0,0 +1,189 @@
+//
+//  KRTexturePNG.cpp
+//  Kraken Engine
+//
+//  Copyright 2025 Kearwood Gilbert. All rights reserved.
+//  
+//  Redistribution and use in source and binary forms, with or without modification, are
+//  permitted provided that the following conditions are met:
+//  
+//  1. Redistributions of source code must retain the above copyright notice, this list of
+//  conditions and the following disclaimer.
+//  
+//  2. Redistributions in binary form must reproduce the above copyright notice, this list
+//  of conditions and the following disclaimer in the documentation and/or other materials
+//  provided with the distribution.
+//  
+//  THIS SOFTWARE IS PROVIDED BY KEARWOOD GILBERT ''AS IS'' AND ANY EXPRESS OR IMPLIED
+//  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+//  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KEARWOOD GILBERT OR
+//  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+//  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+//  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+//  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+//  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+//  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//  
+//  The views and conclusions contained in the software and documentation are those of the
+//  authors and should not be interpreted as representing official policies, either expressed
+//  or implied, of Kearwood Gilbert.
+//
+#include "KRTexturePNG.h"
+#include "KREngine-common.h"
+#include "KRContext.h"
+#include "KRTextureKTX2.h"
+
+using namespace hydra;
+
+#define SWAP_2(x) ( (((x) & 0xff) << 8) | ((uint16_t)(x) >> 8) )
+#define SWAP_4(x) ( ((x) << 24) | (((x) << 8) & 0x00ff0000) |  (((x) >> 8) & 0x0000ff00) |  ((x) >> 24))
+
+#pragma pack(1)
+struct PNG_CHUNK_HEADER
+{
+    uint32_t length;
+    char type[4];
+};
+
+struct PNG_CHUNK_IHDR
+{
+    PNG_CHUNK_HEADER header;
+    uint32_t width;
+    uint32_t height;
+    uint8_t depth;
+    uint8_t colorType;
+    uint8_t compressionMethod;
+    uint8_t filterMethod;
+    uint8_t interlateMethod;
+};
+
+struct PNG_HEADER
+{
+    char magic[8]; // 137 80 78 71 13 10 26 10
+    PNG_CHUNK_IHDR chunk_IHDR; // IHDR always comes first
+};
+#pragma pack()
+
+KRTexturePNG::KRTexturePNG(KRContext& context, Block* data, std::string name) : KRTexture2D(context, data, name)
+{
+  data->lock();
+  PNG_HEADER* pHeader = (PNG_HEADER*)data->getStart();
+  uint8_t expected_magic[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
+  if (memcmp(pHeader->magic, expected_magic, 8) != 0) {
+    assert(false);
+    data->unlock();
+    return; // Not a valid PNG file
+  }
+
+  m_dimensions.x = SWAP_4(pHeader->chunk_IHDR.width);
+  m_dimensions.y = SWAP_4(pHeader->chunk_IHDR.height);
+  m_max_lod_max_dim = m_dimensions.x > m_dimensions.y ? m_dimensions.x : m_dimensions.y;
+  m_min_lod_max_dim = m_max_lod_max_dim; // Mipmaps not yet supported for PNG images
+  switch (pHeader->chunk_IHDR.colorType) {
+  case 0:
+      // greyscale
+      m_imageSize = m_dimensions.x * m_dimensions.y * pHeader->chunk_IHDR.depth / 8;
+      break;
+  case 2:
+      // RGB
+      m_imageSize = m_dimensions.x * m_dimensions.y * pHeader->chunk_IHDR.depth / 8 * 3;
+      break;
+  case 3:
+      // Palette
+      m_imageSize = m_dimensions.x * m_dimensions.y * 3;
+      break;
+  case 4:
+      // Greyscale + alpha
+      m_imageSize = m_dimensions.x * m_dimensions.y * pHeader->chunk_IHDR.depth / 8 * 2;
+      break;
+  case 6:
+      // RGB + Alpha
+      m_imageSize = m_dimensions.x * m_dimensions.y * pHeader->chunk_IHDR.depth / 8 * 4;
+      break;
+  default:
+      assert(false);
+      break;
+  }
+
+  data->unlock();
+}
+
+KRTexturePNG::~KRTexturePNG()
+{
+
+}
+
+bool KRTexturePNG::uploadTexture(KRDevice& device, VkImage& image, int lod_max_dim, int& current_lod_max_dim, bool premultiply_alpha)
+{
+  // TODO - Vulkan Refactoring - Perhaps it would be more efficient to reformat the color channels during the copy to the staging buffer.
+  m_pData->lock();
+  PNG_HEADER* pHeader = (PNG_HEADER*)m_pData->getStart();
+
+  PNG_CHUNK_IHDR* chunk_IHDR = &pHeader->chunk_IHDR;
+
+  PNG_CHUNK_HEADER* chunk = &chunk_IHDR->header;
+
+  uint8_t* palette_data = nullptr;
+  size_t palette_length = 0;
+  uint8_t* alpha_data = nullptr;
+  size_t alpha_length = 0;
+  while(chunk != nullptr)
+  {
+	  chunk = (PNG_CHUNK_HEADER*)((uint8_t*)chunk + sizeof(PNG_CHUNK_HEADER) + SWAP_4(chunk->length));
+	  assert(chunk < (PNG_CHUNK_HEADER*)m_pData->getEnd());
+      if (memcmp(chunk->type, "IEND", 4) == 0) {
+          chunk = nullptr;
+      } else if (memcmp(chunk->type, "PLTE", 4) == 0) {
+          palette_data = (uint8_t*)chunk + sizeof(PNG_CHUNK_HEADER);
+		  palette_length = SWAP_4(chunk->length);
+      } else if (memcmp(chunk->type, "tRNS", 4) == 0) {
+          alpha_data = (uint8_t*)chunk + sizeof(PNG_CHUNK_HEADER);
+          alpha_length = SWAP_4(chunk->length);
+      } else if (memcmp(chunk->type, "IDAT", 4) == 0) {
+          break;
+	  }
+  }
+
+  uint8_t* converted_image = (unsigned char*)malloc(m_imageSize);
+  Vector3i dimensions = { m_dimensions.x, m_dimensions.y, 1 };
+  device.streamUpload((void*)converted_image, m_imageSize, dimensions, image);
+  current_lod_max_dim = m_max_lod_max_dim;
+  m_pData->unlock();
+  return true;
+}
+
+#if !TARGET_OS_IPHONE && !defined(ANDROID)
+
+KRTexture* KRTexturePNG::compress(bool premultiply_alpha)
+{
+  //  TODO - Vulkan refactoring... Not Implemented...
+  assert(false);
+  return nullptr;
+}
+#endif
+
+long KRTexturePNG::getMemRequiredForSize(int max_dim)
+{
+  return m_imageSize;
+}
+
+Vector2i KRTexturePNG::getDimensions() const
+{
+  return m_dimensions;
+}
+
+VkFormat KRTexturePNG::getFormat() const
+{
+  // TODO - We should not automatically add the alpha channel on import
+  return VK_FORMAT_R8G8B8A8_SRGB;
+}
+
+std::string KRTexturePNG::getExtension()
+{
+  return "tga";
+}
+
+int KRTexturePNG::getFaceCount() const
+{
+  return 1;
+}

kraken/resources/texture/KRTexturePNG.h

@@ -0,0 +1,58 @@
+//
+//  KRTexturePNG.h
+//  Kraken Engine
+//
+//  Copyright 2025 Kearwood Gilbert. All rights reserved.
+//  
+//  Redistribution and use in source and binary forms, with or without modification, are
+//  permitted provided that the following conditions are met:
+//  
+//  1. Redistributions of source code must retain the above copyright notice, this list of
+//  conditions and the following disclaimer.
+//  
+//  2. Redistributions in binary form must reproduce the above copyright notice, this list
+//  of conditions and the following disclaimer in the documentation and/or other materials
+//  provided with the distribution.
+//  
+//  THIS SOFTWARE IS PROVIDED BY KEARWOOD GILBERT ''AS IS'' AND ANY EXPRESS OR IMPLIED
+//  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+//  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KEARWOOD GILBERT OR
+//  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+//  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+//  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+//  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+//  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+//  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//  
+//  The views and conclusions contained in the software and documentation are those of the
+//  authors and should not be interpreted as representing official policies, either expressed
+//  or implied, of Kearwood Gilbert.
+//
+
+#pragma once
+
+#include "KRTexture2D.h"
+
+using namespace mimir;
+
+class KRTexturePNG : public KRTexture2D
+{
+public:
+  KRTexturePNG(KRContext& context, Block* data, std::string name);
+  virtual ~KRTexturePNG();
+  virtual std::string getExtension() override;
+
+  bool uploadTexture(KRDevice& device, VkImage& image, int lod_max_dim, int& current_lod_max_dim, bool premultiply_alpha = false) override;
+
+#if !TARGET_OS_IPHONE && !defined(ANDROID)
+  virtual KRTexture* compress(bool premultiply_alpha = false) override;
+#endif
+
+  virtual long getMemRequiredForSize(int max_dim) override;
+  virtual hydra::Vector2i getDimensions() const override;
+  virtual VkFormat getFormat() const override;
+  virtual int getFaceCount() const override;
+private:
+  long m_imageSize;
+  hydra::Vector2i m_dimensions;
+};