/
renderer.go
122 lines (113 loc) · 3.3 KB
/
renderer.go
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// Copyright 2014 Arne Roomann-Kurrik
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package twodee
import (
"fmt"
"github.com/go-gl/gl/v3.3-core/gl"
"strings"
)
type Renderer struct {
Camera *Camera
}
func NewRenderer(camera *Camera) (r *Renderer) {
return &Renderer{
Camera: camera,
}
}
func CreateVAO() (array uint32, err error) {
gl.GenVertexArrays(1, &array)
if e := gl.GetError(); e != 0 {
err = fmt.Errorf("ERROR gl.GenVertexArray %X", e)
return
}
gl.BindVertexArray(array)
if e := gl.GetError(); e != 0 {
err = fmt.Errorf("ERROR array.Bind %X", e)
return
}
return
}
func CreateVBO(size int, data interface{}, usage uint32) (buffer uint32, err error) {
gl.GenBuffers(1, &buffer)
if e := gl.GetError(); e != 0 {
err = fmt.Errorf("ERROR gl.GenBuffer %X", e)
return
}
gl.BindBuffer(gl.ARRAY_BUFFER, buffer)
if e := gl.GetError(); e != 0 {
err = fmt.Errorf("ERROR buffer.Bind %X", e)
return
}
gl.BufferData(gl.ARRAY_BUFFER, size, gl.Ptr(data), usage)
if e := gl.GetError(); e != 0 {
err = fmt.Errorf("ERROR gl.BufferData %X", e)
return
}
gl.BindBuffer(gl.ARRAY_BUFFER, 0)
if e := gl.GetError(); e != 0 {
err = fmt.Errorf("ERROR buffer.Unbind %X", e)
return
}
return
}
func CompileShader(stype uint32, source string) (shader uint32, err error) {
csource := gl.Str(source)
shader = gl.CreateShader(stype)
gl.ShaderSource(shader, 1, &csource, nil)
gl.CompileShader(shader)
var status int32
if gl.GetShaderiv(shader, gl.COMPILE_STATUS, &status); status == gl.FALSE {
var length int32
gl.GetShaderiv(shader, gl.INFO_LOG_LENGTH, &length)
log := strings.Repeat("\x00", int(length+1))
gl.GetShaderInfoLog(shader, length, nil, gl.Str(log))
err = fmt.Errorf("ERROR shader compile:\n%s", log)
}
return
}
func LinkProgram(vertex uint32, fragment uint32) (program uint32, err error) {
program = gl.CreateProgram()
gl.AttachShader(program, vertex)
gl.AttachShader(program, fragment)
gl.BindFragDataLocation(program, 0, gl.Str("v_FragData\x00"))
if e := gl.GetError(); e != 0 {
err = fmt.Errorf("ERROR program.BindFragDataLocation %X", e)
return
}
gl.LinkProgram(program)
var status int32
if gl.GetProgramiv(program, gl.LINK_STATUS, &status); status == gl.FALSE {
var length int32
gl.GetProgramiv(program, gl.INFO_LOG_LENGTH, &length)
log := strings.Repeat("\x00", int(length+1))
gl.GetProgramInfoLog(program, length, nil, gl.Str(log))
err = fmt.Errorf("ERROR program link:\n%s", log)
}
gl.DeleteShader(vertex)
gl.DeleteShader(fragment)
return
}
func BuildProgram(vsrc string, fsrc string) (program uint32, err error) {
var (
vertex uint32
fragment uint32
)
if vertex, err = CompileShader(gl.VERTEX_SHADER, vsrc); err != nil {
return
}
if fragment, err = CompileShader(gl.FRAGMENT_SHADER, fsrc); err != nil {
return
}
return LinkProgram(vertex, fragment)
}