func (glRenderer *OpenglRenderer) enableDepthMask(depthMask bool) {
if depthMask == glRenderer.depthMast {
return
}
gl.DepthMask(depthMask)
glRenderer.depthMast = depthMask
}
func (p *LightPass) DrawPass(scene *Scene) {
/* use light pass shader */
p.Material.Use()
shader := p.Material.Shader
/* compute camera view projection inverse */
vp := scene.Camera.Projection.Mul4(scene.Camera.View)
vp_inv := vp.Inv()
shader.Matrix4f("cameraInverse", &vp_inv[0])
/* clear */
gl.ClearColor(0.9, 0.9, 0.9, 1.0)
gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
/* set blending mode to additive */
gl.DepthMask(false)
/* draw lights */
lights := scene.FindLights()
last := len(lights) - 1
for i, light := range lights {
if i == 1 {
/* first light pass we want the shader to restore the depth buffer
* then, disable depth masking so that multiple lights can be drawn */
gl.BlendFunc(gl.ONE, gl.ONE)
}
if i == last {
gl.DepthMask(true)
}
/* draw shadow pass for this light into shadow map */
p.Shadows.DrawPass(scene, &light)
/* use light pass shader */
p.Material.Use()
/* compute world to lightspace (light view projection) matrix */
lp := light.Projection
lv := mgl.LookAtV(light.Position, mgl.Vec3{}, mgl.Vec3{0, 1, 0}) // only for directional light
lvp := lp.Mul4(lv)
shader.Matrix4f("light_vp", &lvp[0])
/* set light uniform attributes */
shader.Vec3("light.Position", &light.Position)
shader.Vec3("light.Color", &light.Color)
shader.Int32("light.Type", int32(light.Type))
shader.Float("light.Range", light.Range)
shader.Float("light.attenuation.Constant", light.Attenuation.Constant)
shader.Float("light.attenuation.Linear", light.Attenuation.Linear)
shader.Float("light.attenuation.Quadratic", light.Attenuation.Quadratic)
/* render light */
gl.Viewport(0, 0, int32(scene.Camera.Width), int32(scene.Camera.Height))
p.quad.Draw()
}
/* reset GL state */
gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
}