func (s *MainState) Render() error { gl.UseProgram(s.program) gl.UniformMatrix4fv(s.projectionUniform, 1, false, &s.projection[0]) /* gl.BindVertexArray(s.vao) gl.BindBuffer(gl.ARRAY_BUFFER, s.vbo) */ gl.BufferData( gl.ARRAY_BUFFER, int(PARTICLE_COUNT_DEFAULT*unsafe.Sizeof([2]float32{})), nil, gl.STREAM_DRAW) data, err := sliceMap2Float32Buffer(gl.WRITE_ONLY, PARTICLE_COUNT_DEFAULT) if err != nil { return err } for i := range data { p := &s.space.Particles[i] if p == nil { return fmt.Errorf("no particle of id %d", i) } data[i][0] = float32(p.Position.X) data[i][1] = float32(p.Position.Y) } gl.UnmapBuffer(gl.ARRAY_BUFFER) data = nil positionAttrib := uint32(gl.GetAttribLocation(s.program, gl.Str("position\x00"))) gl.EnableVertexAttribArray(positionAttrib) gl.VertexAttribPointer(positionAttrib, 2, gl.FLOAT, false, 0, gl.PtrOffset(0)) gl.ClearColor(0, 0, 0, 1) gl.Clear(gl.COLOR_BUFFER_BIT) gl.DrawArrays(gl.POINTS, 0, PARTICLE_COUNT_DEFAULT) return nil }
func (s *MainState) Render() error { program := s.program gl.UseProgram(program) projectionUniform := gl.GetUniformLocation(program, gl.Str("projection\x00")) gl.UniformMatrix4fv(projectionUniform, 1, false, &projection[0]) gl.Flush() buffer := s.vertexBuffer gl.BindBuffer(gl.ARRAY_BUFFER, buffer) gl.BufferData( gl.ARRAY_BUFFER, int(PARTICLE_COUNT_DEFAULT*unsafe.Sizeof([2]float32{})), nil, gl.STREAM_DRAW) dataPointer := gl.MapBuffer(gl.ARRAY_BUFFER, gl.WRITE_ONLY) if dataPointer == nil { return fmt.Errorf("buffer data pointer is nil") } data := (*[PARTICLE_COUNT_DEFAULT][2]float32)(dataPointer) gl.ClearColor(0, 0, 0, 1) gl.Clear(gl.COLOR_BUFFER_BIT) for i := range data { p := s.space.Particle(i) if p == nil { return fmt.Errorf("no particle of id %d", i) } data[i][0] = float32(p.Position.X) data[i][1] = float32(p.Position.Y) } gl.UnmapBuffer(gl.ARRAY_BUFFER) gl.DrawArrays(gl.POINTS, 0, PARTICLE_COUNT_DEFAULT) return nil }