Example #1
0
func (r *Renderer) draw(geometry *Geometry, count int) (err error) {
	if count <= 0 {
		return
	}
	r.vbo.Upload(r.buffer, count*int(r.stride))
	gl.DrawArraysInstanced(gl.TRIANGLES, 0, int32(len(geometry.Points)), int32(count))
	if e := gl.GetError(); e != 0 {
		err = fmt.Errorf("ERROR: OpenGL error %X", e)
	}
	return
}
Example #2
0
func (tr *SpriteRenderer) Draw(instances []SpriteConfig) error {
	var (
		bytesNeeded int
		byteoffset  int
		count       int32
		data        unsafe.Pointer
		float       float32 = 0
		floatSize   uint32
		i           uint32
		offset      unsafe.Pointer
		sprite      SpriteConfig
		stride      int32
	)

	floatSize = uint32(unsafe.Sizeof(float))
	stride = int32(unsafe.Sizeof(sprite))

	gl.UseProgram(tr.program)
	gl.Uniform1i(tr.textureUnitLoc, 0)

	// Instance data binding
	gl.BindBuffer(gl.ARRAY_BUFFER, tr.instanceVBO)
	count = int32(len(instances))
	bytesNeeded = int(stride * count)
	data = gl.Ptr(instances)
	if bytesNeeded > tr.instanceBytes {
		gl.BufferData(gl.ARRAY_BUFFER, bytesNeeded, data, gl.STREAM_DRAW)
		tr.instanceBytes = bytesNeeded
	} else {
		gl.BufferSubData(gl.ARRAY_BUFFER, 0, bytesNeeded, data)
	}

	gl.EnableVertexAttribArray(tr.translationLoc)
	gl.VertexAttribPointer(tr.translationLoc, 3, gl.FLOAT, false, stride, tr.offAttrX)
	gl.VertexAttribDivisor(tr.translationLoc, 1)

	gl.EnableVertexAttribArray(tr.rotationLoc)
	gl.VertexAttribPointer(tr.rotationLoc, 3, gl.FLOAT, false, stride, tr.offAttrRotationX)
	gl.VertexAttribDivisor(tr.rotationLoc, 1)

	gl.EnableVertexAttribArray(tr.scaleLoc)
	gl.VertexAttribPointer(tr.scaleLoc, 3, gl.FLOAT, false, stride, tr.offAttrScaleX)
	gl.VertexAttribDivisor(tr.scaleLoc, 1)

	gl.EnableVertexAttribArray(tr.colorLoc)
	gl.VertexAttribPointer(tr.colorLoc, 4, gl.FLOAT, false, stride, tr.offAttrColor)
	gl.VertexAttribDivisor(tr.colorLoc, 1)

	for i = 0; i < 4; i++ {
		byteoffset = int(i * 4 * floatSize)
		offset = gl.PtrOffset(tr.offAttrPointAdj + byteoffset)
		gl.EnableVertexAttribArray(tr.pointAdjLoc + i)
		gl.VertexAttribPointer(tr.pointAdjLoc+i, 4, gl.FLOAT, false, stride, offset)
		gl.VertexAttribDivisor(tr.pointAdjLoc+i, 1)

		offset = gl.PtrOffset(tr.offAttrTextureAdj + byteoffset)
		gl.EnableVertexAttribArray(tr.textureAdjLoc + i)
		gl.VertexAttribPointer(tr.textureAdjLoc+i, 4, gl.FLOAT, false, stride, offset)
		gl.VertexAttribDivisor(tr.textureAdjLoc+i, 1)
	}
	// Projection
	gl.UniformMatrix4fv(tr.projectionLoc, 1, false, &tr.Renderer.Camera.Projection[0])

	// Actually draw.
	gl.DrawArraysInstanced(gl.TRIANGLES, 0, 6, int32(len(instances)))

	// Undo instance attr repetition.
	gl.VertexAttribDivisor(tr.translationLoc, 0)
	gl.VertexAttribDivisor(tr.rotationLoc, 0)
	gl.VertexAttribDivisor(tr.scaleLoc, 0)
	gl.VertexAttribDivisor(tr.colorLoc, 0)
	for i = 0; i < 4; i++ {
		gl.VertexAttribDivisor(tr.pointAdjLoc+i, 0)
		gl.VertexAttribDivisor(tr.textureAdjLoc+i, 0)
	}

	gl.BindBuffer(gl.ARRAY_BUFFER, 0)
	return nil
}