Add image from an opengl texture (#74)

Author: EldoDebug

platform/cc/Image.cc

@@ -5,6 +5,37 @@
 #include "SkImage.h"
 #include "SkShader.h"
 #include "interop.hh"
+#include "GrBackendSurface.h"
+#include "GrDirectContext.h"
+#include "include/gpu/GrBackendSurface.h"
+#include "include/gpu/ganesh/SkImageGanesh.h"
+#include "include/gpu/gl/GrGLTypes.h"
+
+extern "C" JNIEXPORT jlong JNICALL Java_io_github_humbleui_skija_Image__1nAdoptGLTextureFrom
+  (JNIEnv* env, jclass jclass, jlong contextPtr, jint textureId, jint target, jint width, jint height, jint format, jint surfaceOrigin, jint colorType) {
+
+    GrDirectContext* context = reinterpret_cast<GrDirectContext*>(static_cast<uintptr_t>(contextPtr));
+
+    GrGLTextureInfo textureInfo;
+    textureInfo.fID = static_cast<GrGLuint>(textureId);
+    textureInfo.fTarget = static_cast<GrGLenum>(target);
+    textureInfo.fFormat = static_cast<GrGLenum>(format);
+    
+    GrBackendTexture backendTexture = GrBackendTexture(
+        width, height,
+        skgpu::Mipmapped::kYes,
+        textureInfo
+    );
+
+    sk_sp<SkImage> image = SkImages::AdoptTextureFrom(
+        context,
+        backendTexture,
+        static_cast<GrSurfaceOrigin>(surfaceOrigin),
+        static_cast<SkColorType>(colorType)
+    );
+
+    return reinterpret_cast<jlong>(image.release());
+}
 
 extern "C" JNIEXPORT jlong JNICALL Java_io_github_humbleui_skija_Image__1nMakeRasterFromBytes
   (JNIEnv* env, jclass jclass, jint width, jint height, jint colorType, jint alphaType, jlong colorSpacePtr, jbyteArray bytesArr, jlong rowBytes) {

shared/java/Image.java

@@ -23,6 +23,43 @@ public static Image makeRaster(ImageInfo imageInfo, byte[] bytes, long rowBytes)
         return makeRasterFromBytes(imageInfo, bytes, rowBytes);
     }
 
+    /**
+     * <p>Creates Image from an OpenGL texture.</p>
+     *
+     * <p>Image is returned if the texture is valid. Valid texture parameters include:</p>
+     * <ul>
+     * <li>textureId is a valid OpenGL texture ID;</li>
+     * <li>width and height are greater than zero;</li>
+     * <li>ColorType and AlphaType are valid, and ColorType is not ColorType.UNKNOWN;</li>
+     * <li>colorSpace is a valid SkColorSpace;</li>
+     * </ul>
+     *
+     * @param context     GrDirectContext
+     * @param textureId   OpenGL texture ID
+     * @param width       width of the texture
+     * @param height      height of the texture
+     * @param colorType   color type of the texture
+     * @return            Image
+     */
+    public static Image adoptGLTextureFrom(DirectContext context, int textureId, int target, int width, int height, int format, SurfaceOrigin surfaceOrigin, ColorType colorType) {
+        try {
+            Stats.onNativeCall();
+            long ptr = _nAdoptGLTextureFrom(Native.getPtr(context),
+                                            textureId,
+                                            target,
+                                            width,
+                                            height,
+                                            format,
+                                            surfaceOrigin.ordinal(),
+                                            colorType.ordinal());
+            if (ptr == 0)
+                throw new RuntimeException("Failed to adoptGLTextureFrom " + textureId + " " + width + "x" + height);
+            return new Image(ptr);
+        } finally {
+            ReferenceUtil.reachabilityFence(context);
+        }
+    }
+        
     /**
      * <p>Creates Image from pixels.</p>
      *
@@ -382,6 +419,7 @@ public boolean scalePixels(@NotNull Pixmap dst, SamplingMode samplingMode, boole
         }
     }
 
+    @ApiStatus.Internal public static native long _nAdoptGLTextureFrom(long contextPtr, int textureId, int target, int width, int height, int format, int surfaceOrigin, int colorType);
     @ApiStatus.Internal public static native long _nMakeRasterFromBytes(int width, int height, int colorType, int alphaType, long colorSpacePtr, byte[] pixels, long rowBytes);
     @ApiStatus.Internal public static native long _nMakeRasterFromData(int width, int height, int colorType, int alphaType, long colorSpacePtr, long dataPtr, long rowBytes);
     @ApiStatus.Internal public static native long _nMakeRasterFromBitmap(long bitmapPtr);