Remove the need for copysource and copydest buffer usage flags.

src/modules/graphics/Buffer.cpp

@@ -46,14 +46,10 @@ Buffer::Buffer(Graphics *gfx, const Settings &settings, const std::vector<DataDe
 	const auto &caps = gfx->getCapabilities();
 	bool supportsGLSL3 = caps.features[Graphics::FEATURE_GLSL3];
 
-	bool indexbuffer = settings.usageFlags & BUFFERUSAGEFLAG_INDEX;
-	bool vertexbuffer = settings.usageFlags & BUFFERUSAGEFLAG_VERTEX;
-	bool texelbuffer = settings.usageFlags & BUFFERUSAGEFLAG_TEXEL;
-	bool storagebuffer = settings.usageFlags & BUFFERUSAGEFLAG_SHADER_STORAGE;
-	bool copydest = settings.usageFlags & BUFFERUSAGEFLAG_COPY_DEST;
-
-	if (!indexbuffer && !vertexbuffer && !texelbuffer && !storagebuffer)
-		throw love::Exception("Buffer must be created with at least one buffer type (index, vertex, texel, or shaderstorage).");
+	bool indexbuffer = usageFlags & BUFFERUSAGEFLAG_INDEX;
+	bool vertexbuffer = usageFlags & BUFFERUSAGEFLAG_VERTEX;
+	bool texelbuffer = usageFlags & BUFFERUSAGEFLAG_TEXEL;
+	bool storagebuffer = usageFlags & BUFFERUSAGEFLAG_SHADER_STORAGE;
 
 	if (texelbuffer && !caps.features[Graphics::FEATURE_TEXEL_BUFFER])
 		throw love::Exception("Texel buffers are not supported on this system.");
@@ -61,8 +57,8 @@ Buffer::Buffer(Graphics *gfx, const Settings &settings, const std::vector<DataDe
 	if (storagebuffer && !caps.features[Graphics::FEATURE_GLSL4])
 		throw love::Exception("Shader Storage buffers are not supported on this system (GLSL 4 support is necessary.)");
 
-	if (copydest && dataUsage == BUFFERDATAUSAGE_STREAM)
-		throw love::Exception("Buffers created with 'stream' data usage cannot be used as a copy destination.");
+	if (storagebuffer && dataUsage == BUFFERDATAUSAGE_STREAM)
+		throw love::Exception("Buffers created with 'stream' data usage cannot be used as a shader storage buffer.");
 
 	size_t offset = 0;
 	size_t stride = 0;

src/modules/graphics/Graphics.cpp

@@ -1058,15 +1058,12 @@ void Graphics::copyBuffer(Buffer *source, Buffer *dest, size_t sourceoffset, siz
 	if (!capabilities.features[FEATURE_COPY_BUFFER])
 		throw love::Exception("Buffer copying is not supported on this system.");
 
-	if (!(source->getUsageFlags() & BUFFERUSAGEFLAG_COPY_SOURCE))
-		throw love::Exception("Copy source buffer must be created with the copysource flag.");
-
-	if (!(dest->getUsageFlags() & BUFFERUSAGEFLAG_COPY_DEST))
-		throw love::Exception("Copy destination buffer must be created with the copydest flag.");
-
 	Range sourcerange(sourceoffset, size);
 	Range destrange(destoffset, size);
 
+	if (dest->getDataUsage() == BUFFERDATAUSAGE_STREAM)
+		throw love::Exception("Buffers created with 'stream' data usage cannot be used as a copy destination.");
+
 	if (sourcerange.getMax() >= source->getSize())
 		throw love::Exception("Buffer copy source offset and size doesn't fit within the source Buffer's size.");
 

src/modules/graphics/opengl/Buffer.cpp

@@ -80,10 +80,6 @@ Buffer::Buffer(love::graphics::Graphics *gfx, const Settings &settings, const st
 		mapUsage = BUFFERUSAGE_INDEX;
 	else  if (usageFlags & BUFFERUSAGEFLAG_SHADER_STORAGE)
 		mapUsage = BUFFERUSAGE_SHADER_STORAGE;
-	else if (usageFlags & BUFFERUSAGEFLAG_COPY_SOURCE)
-		mapUsage = BUFFERUSAGE_COPY_SOURCE;
-	else if (usageFlags & BUFFERUSAGEFLAG_COPY_DEST)
-		mapUsage = BUFFERUSAGE_COPY_DEST;
 
 	target = OpenGL::getGLBufferType(mapUsage);
 
@@ -261,8 +257,9 @@ void Buffer::fill(size_t offset, size_t size, const void *data)
 
 void Buffer::copyTo(love::graphics::Buffer *dest, size_t sourceoffset, size_t destoffset, size_t size)
 {
-	gl.bindBuffer(BUFFERUSAGE_COPY_SOURCE, buffer);
-	gl.bindBuffer(BUFFERUSAGE_COPY_DEST, ((Buffer *) dest)->buffer);
+	// TODO: tracked state for these bind types?
+	glBindBuffer(GL_COPY_READ_BUFFER, buffer);
+	glBindBuffer(GL_COPY_WRITE_BUFFER, ((Buffer *) dest)->buffer);
 
 	glCopyBufferSubData(GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, sourceoffset, destoffset, size);
 }

src/modules/graphics/opengl/Graphics.cpp

@@ -497,8 +497,7 @@ static bool computeDispatchBarriers(Shader *shader, GLbitfield &preDispatchBarri
 		if (usage & BUFFERUSAGEFLAG_VERTEX)
 			postDispatchBarriers |= GL_VERTEX_ATTRIB_ARRAY_BARRIER_BIT;
 
-		if (usage & (BUFFERUSAGEFLAG_COPY_SOURCE | BUFFERUSAGEFLAG_COPY_DEST))
-			postDispatchBarriers |= GL_PIXEL_BUFFER_BARRIER_BIT;
+		postDispatchBarriers |= GL_PIXEL_BUFFER_BARRIER_BIT;
 	}
 
 	for (const auto &binding : shader->getStorageTextureBindings())

src/modules/graphics/opengl/OpenGL.cpp

@@ -666,8 +666,6 @@ GLenum OpenGL::getGLBufferType(BufferUsage usage)
 		case BUFFERUSAGE_INDEX: return GL_ELEMENT_ARRAY_BUFFER;
 		case BUFFERUSAGE_TEXEL: return GL_TEXTURE_BUFFER;
 		case BUFFERUSAGE_SHADER_STORAGE: return GL_SHADER_STORAGE_BUFFER;
-		case BUFFERUSAGE_COPY_SOURCE: return GL_COPY_READ_BUFFER;
-		case BUFFERUSAGE_COPY_DEST: return GL_COPY_WRITE_BUFFER;
 		case BUFFERUSAGE_MAX_ENUM: return GL_ZERO;
 	}
 
@@ -1483,9 +1481,6 @@ bool OpenGL::isBufferUsageSupported(BufferUsage usage) const
 		return GLAD_VERSION_3_1;
 	case BUFFERUSAGE_SHADER_STORAGE:
 		return (GLAD_VERSION_4_3 && isCoreProfile()) || GLAD_ES_VERSION_3_1;
-	case BUFFERUSAGE_COPY_SOURCE:
-	case BUFFERUSAGE_COPY_DEST:
-		return GLAD_VERSION_3_1 || GLAD_ES_VERSION_3_0;
 	case BUFFERUSAGE_MAX_ENUM:
 		return false;
 	}
@@ -1530,6 +1525,11 @@ bool OpenGL::isMultiFormatMRTSupported() const
 	return getMaxRenderTargets() > 1 && (GLAD_ES_VERSION_3_0 || GLAD_VERSION_3_0 || GLAD_ARB_framebuffer_object);
 }
 
+bool OpenGL::isCopyBufferSupported() const
+{
+	return GLAD_VERSION_3_1 || GLAD_ES_VERSION_3_0;
+}
+
 int OpenGL::getMax2DTextureSize() const
 {
 	return std::max(max2DTextureSize, 1);

src/modules/graphics/opengl/OpenGL.h

@@ -371,6 +371,7 @@ public:
 	bool isSamplerLODBiasSupported() const;
 	bool isBaseVertexSupported() const;
 	bool isMultiFormatMRTSupported() const;
+	bool isCopyBufferSupported() const;
 
 	/**
 	 * Returns the maximum supported width or height of a texture.

src/modules/graphics/vertex.cpp

@@ -343,8 +343,6 @@ STRINGMAP_BEGIN(BufferUsage, BUFFERUSAGE_MAX_ENUM, bufferUsageName)
 	{ "index",         BUFFERUSAGE_INDEX          },
 	{ "texel",         BUFFERUSAGE_TEXEL          },
 	{ "shaderstorage", BUFFERUSAGE_SHADER_STORAGE },
-	{ "copysource",    BUFFERUSAGE_COPY_SOURCE    },
-	{ "copydest",      BUFFERUSAGE_COPY_DEST      },
 }
 STRINGMAP_END(BufferUsage, BUFFERUSAGE_MAX_ENUM, bufferUsageName)
 

src/modules/graphics/vertex.h

@@ -60,8 +60,6 @@ enum BufferUsage
 	BUFFERUSAGE_INDEX,
 	BUFFERUSAGE_TEXEL,
 	BUFFERUSAGE_SHADER_STORAGE,
-	BUFFERUSAGE_COPY_SOURCE,
-	BUFFERUSAGE_COPY_DEST,
 	BUFFERUSAGE_MAX_ENUM
 };
 
@@ -72,8 +70,6 @@ enum BufferUsageFlags
 	BUFFERUSAGEFLAG_INDEX = 1 << BUFFERUSAGE_INDEX,
 	BUFFERUSAGEFLAG_TEXEL = 1 << BUFFERUSAGE_TEXEL,
 	BUFFERUSAGEFLAG_SHADER_STORAGE = 1 << BUFFERUSAGE_SHADER_STORAGE,
-	BUFFERUSAGEFLAG_COPY_SOURCE = 1 << BUFFERUSAGE_COPY_SOURCE,
-	BUFFERUSAGEFLAG_COPY_DEST = 1 << BUFFERUSAGE_COPY_DEST,
 };
 
 enum IndexDataType