Add generic VBO drawing class called GFX (for lack of better name).

lib/ivis_opengl/pieblitfunc.cpp

@@ -67,6 +67,81 @@ struct PIERECT  ///< Screen rectangle.
  */
 /***************************************************************************/
 
+GFX::GFX(GLenum drawType, int coordsPerVertex) : mdrawType(drawType), mCoordsPerVertex(coordsPerVertex), mSize(0)
+{
+	glGenBuffers(VBO_MINIMAL, mBuffers);
+	glGenTextures(1, &mTexture);
+}
+
+void GFX::loadTexture(const char *filename, GLenum filter)
+{
+	const char *extension = strrchr(filename, '.'); // determine the filetype
+	iV_Image image;
+	if (!extension || strcmp(extension, ".png") != 0)
+	{
+		debug(LOG_ERROR, "Bad image filename: %s", filename);
+		return;
+	}
+	if (iV_loadImage_PNG(filename, &image))
+	{
+		makeTexture(image.width, image.height, filter, iV_getPixelFormat(&image), image.bmp);
+		iV_unloadImage(&image);
+	}
+}
+
+void GFX::makeTexture(int width, int height, GLenum filter, GLenum format, const GLvoid *image)
+{
+	pie_SetTexturePage(TEXPAGE_EXTERN);
+	glBindTexture(GL_TEXTURE_2D, mTexture);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, format, GL_UNSIGNED_BYTE, image);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filter);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
+	mWidth = width;
+	mHeight = height;
+	mFormat = format;
+}
+
+void GFX::updateTexture(const void *image, int width, int height)
+{
+	if (width == -1) width = mWidth;
+	if (height == -1) height = mHeight;
+	pie_SetTexturePage(TEXPAGE_EXTERN);
+	glBindTexture(GL_TEXTURE_2D, mTexture);
+	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, mFormat, GL_UNSIGNED_BYTE, image);
+}
+
+void GFX::buffers(int vertices, const GLvoid *vertBuf, const GLvoid *texBuf)
+{
+	glBindBuffer(GL_ARRAY_BUFFER, mBuffers[VBO_TEXCOORD]);
+	glBufferData(GL_ARRAY_BUFFER, vertices * 2 * sizeof(GLfloat), texBuf, GL_STATIC_DRAW);
+	glBindBuffer(GL_ARRAY_BUFFER, mBuffers[VBO_VERTEX]);
+	glBufferData(GL_ARRAY_BUFFER, vertices * mCoordsPerVertex * sizeof(GLfloat), vertBuf, GL_STATIC_DRAW);
+	glBindBuffer(GL_ARRAY_BUFFER, 0);
+	mSize = vertices;
+}
+
+void GFX::draw()
+{
+	pie_SetTexturePage(TEXPAGE_EXTERN);
+	glBindTexture(GL_TEXTURE_2D, mTexture);
+	glEnableClientState(GL_VERTEX_ARRAY);
+	glEnableClientState(GL_TEXTURE_COORD_ARRAY);
+	glBindBuffer(GL_ARRAY_BUFFER, mBuffers[VBO_TEXCOORD]); glTexCoordPointer(2, GL_FLOAT, 0, NULL);
+	glBindBuffer(GL_ARRAY_BUFFER, mBuffers[VBO_VERTEX]); glVertexPointer(mCoordsPerVertex, GL_FLOAT, 0, NULL);
+	glDrawArrays(mdrawType, 0, mSize);
+	glDisableClientState(GL_VERTEX_ARRAY);
+	glDisableClientState(GL_TEXTURE_COORD_ARRAY);
+	glBindBuffer(GL_ARRAY_BUFFER, 0);
+}
+
+GFX::~GFX()
+{
+	glDeleteBuffers(VBO_MINIMAL, mBuffers);
+	glDeleteTextures(1, &mTexture);
+}
+
 void iV_Line(int x0, int y0, int x1, int y1, PIELIGHT colour)
 {
 	pie_SetTexturePage(TEXPAGE_NONE);

lib/ivis_opengl/pieblitfunc.h

@@ -49,10 +49,47 @@
 
 /***************************************************************************/
 /*
- *	Global Variables
+ *	Global Classes
  */
 /***************************************************************************/
 
+/// Generic graphics using VBOs drawing class
+class GFX
+{
+public:
+	/// Initialize class and allocate GPU resources
+	GFX(GLenum drawType = GL_TRIANGLES, int coordsPerVertex = 3);
+
+	/// Destroy GPU held resources
+	~GFX();
+
+	/// Load texture data from file, allocate space for it, and put it on the GPU
+	void loadTexture(const char *filename, GLenum filter = GL_LINEAR);
+
+	/// Allocate space on the GPU for texture of given parameters. If image is non-NULL,
+	/// then that memory buffer is uploaded to the GPU.
+	void makeTexture(int width, int height, GLenum filter = GL_LINEAR, GLenum format = GL_RGBA, const GLvoid *image = NULL);
+
+	/// Upload given memory buffer to already allocated texture space on the GPU
+	void updateTexture(const GLvoid *image, int width = -1, int height = -1);
+
+	/// Upload vertex and texture buffer data to the GPU
+	void buffers(int vertices, const GLvoid *vertBuf, const GLvoid *texBuf);
+
+	/// Draw everything
+	void draw();
+
+private:
+	GLenum mFormat;
+	int mWidth;
+	int mHeight;
+	GLenum mdrawType;
+	int mCoordsPerVertex;
+	GLuint mBuffers[VBO_COUNT];
+	GLuint mTexture;
+	int mSize;
+};
+
 /***************************************************************************/
 /*
  *	Global ProtoTypes