// update handles user input.
func (rt *rtrace) update(dev device.Device) {
pressed := dev.Update()
if pressed.Resized {
_, _, ww, wh := dev.Size()
gl.Viewport(0, 0, int32(ww), int32(wh))
}
}
// resize handles user screen/window changes.
func (ld *ldtag) resize(x, y, width, height int) {
gl.Viewport(0, 0, int32(width), int32(height))
ld.persp.Persp(60, float64(width)/float64(height), 0.1, 50)
}
// resize handles user screen/window changes.
func (sf *sftag) resize(x, y, width, height int) {
gl.Viewport(0, 0, int32(width), int32(height))
}
// Render implementation.
// FUTURE: all kinds of possible optimizations that would need to be
// profiled before implementing.
// • group by vao to avoid switching vao's.
// • group by texture to avoid switching textures.
// • use interleaved vertex data.
// • uniform buffers http://www.opengl.org/wiki/Uniform_Buffer_Object.
// • ... lots more possiblities... leave your fav here.
func (gc *opengl) Render(dr Draw) {
d, ok := dr.(*draw)
if !ok || d == nil {
return
}
// switch state only if necessary.
if gc.depthTest != d.depth {
if d.depth {
gl.Enable(gl.DEPTH_TEST)
} else {
gl.Disable(gl.DEPTH_TEST)
}
gc.depthTest = d.depth
}
// switch render framebuffer only if necessary. The framebuffer
// is used to render to a texture associated with a framebuffer.
if gc.fbo != d.fbo {
gl.BindFramebuffer(gl.FRAMEBUFFER, d.fbo)
if d.fbo == 0 {
gl.Viewport(0, 0, gc.vw, gc.vh)
} else {
gl.Clear(gl.DEPTH_BUFFER_BIT)
gl.Viewport(0, 0, 1024, 1024) // size convention for framebuffer texture.
}
gc.fbo = d.fbo
}
// switch shaders only if necessary.
if gc.shader != d.shader {
gl.UseProgram(d.shader)
gc.shader = d.shader
}
// Ask the model to bind its provisioned uniforms.
// FUTURE: only need to bind uniforms that have changed.
gc.bindUniforms(d)
// bind the data buffers and render.
gl.BindVertexArray(d.vao)
switch d.mode {
case LINES:
gl.PolygonMode(gl.FRONT_AND_BACK, gl.LINE)
gl.DrawElements(gl.LINES, d.numFaces, gl.UNSIGNED_SHORT, 0)
gl.PolygonMode(gl.FRONT_AND_BACK, gl.FILL)
case POINTS:
gl.Enable(gl.PROGRAM_POINT_SIZE)
gl.DrawArrays(gl.POINTS, 0, d.numVerts)
gl.Disable(gl.PROGRAM_POINT_SIZE)
case TRIANGLES:
if len(d.texs) > 1 && d.texs[0].fn > 0 {
// Multiple textures on one model specify which verticies they apply to.
for _, tex := range d.texs {
// Use the same texture unit and sampler. Just update which
// image is being sampled.
gl.BindTexture(gl.TEXTURE_2D, tex.tid)
// fn is the number of triangles, 3 indicies per triangle.
// f0 is the offset in triangles where each triangle has 3 indicies
// of 2 bytes (uShort) each.
gl.DrawElements(gl.TRIANGLES, tex.fn*3, gl.UNSIGNED_SHORT, int64(3*2*tex.f0))
}
} else {
// Single textures are handled with a standard bindUniforms
gl.DrawElements(gl.TRIANGLES, d.numFaces, gl.UNSIGNED_SHORT, 0)
}
}
}
func (gc *opengl) Viewport(width int, height int) {
gc.vw, gc.vh = int32(width), int32(height)
gl.Viewport(0, 0, int32(width), int32(height))
}
// resize sets the view port size. User resizes are ignored.
func (tag *trtag) resize(width int, height int) {
gl.Viewport(0, 0, int32(width), int32(height))
tag.persp.Persp(60, float64(width)/float64(height), 0.1, 50)
}
