Example #1
0
File: opengl.go Project: toophy/vu
// 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 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)
		}
	}
}
Example #2
0
File: ld.go Project: toophy/vu
// initScene is called once on startup to load the 3D data.
func (ld *ldtag) initScene() {
	ld.persp = lin.NewM4()
	ld.mvp64 = lin.NewM4()
	ld.mvp = render.NewMvp()
	gl.Init()
	ldr := load.NewLoader()
	meshes, _ := ldr.Obj("monkey")
	mesh := meshes[0]
	ld.faceCount = int32(len(mesh.F))

	// Gather the one scene into this one vertex array object.
	gl.GenVertexArrays(1, &ld.vao)
	gl.BindVertexArray(ld.vao)

	// vertex data.
	var vbuff uint32
	gl.GenBuffers(1, &vbuff)
	gl.BindBuffer(gl.ARRAY_BUFFER, vbuff)
	gl.BufferData(gl.ARRAY_BUFFER, int64(len(mesh.V)*4), gl.Pointer(&(mesh.V[0])), gl.STATIC_DRAW)
	gl.VertexAttribPointer(0, 3, gl.FLOAT, false, 0, 0)
	gl.EnableVertexAttribArray(0)

	// normal data.
	var nbuff uint32
	gl.GenBuffers(1, &nbuff)
	gl.BindBuffer(gl.ARRAY_BUFFER, nbuff)
	gl.BufferData(gl.ARRAY_BUFFER, int64(len(mesh.N)*4), gl.Pointer(&(mesh.N[0])), gl.STATIC_DRAW)
	gl.VertexAttribPointer(1, 3, gl.FLOAT, false, 0, 0)
	gl.EnableVertexAttribArray(1)

	// faces data, uint32 in this case, so 4 bytes per element.
	var fbuff uint32
	gl.GenBuffers(1, &fbuff)
	gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, fbuff)
	gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, int64(len(mesh.F)*2), gl.Pointer(&(mesh.F[0])), gl.STATIC_DRAW)

	ld.initShader()
	gl.ClearColor(0.2, 0.2, 0.2, 1.0)
	gl.Enable(gl.DEPTH_TEST)
	gl.Enable(gl.CULL_FACE)

	// set the initial perspetive matrix.
	ld.resize(0, 0, 800, 600)
}
Example #3
0
// Renderer implementation.
func (gc *opengl) Enable(attribute uint32, enabled bool) {
	switch attribute {
	case CULL, DEPTH:
		if enabled {
			gl.Enable(attribute)
		} else {
			gl.Disable(attribute)
		}
	case BLEND:
		if enabled {
			gl.Enable(attribute)

			// Using non pre-multiplied alpha colour data so...
			gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
		} else {
			gl.Disable(attribute)
		}
	}
}
Example #4
0
File: tr.go Project: skyview059/vu
// initScene is one time initialization that creates a single VAO
func (tag *trtag) initScene() {
	tag.mvp64 = lin.NewM4()
	tag.persp = lin.NewM4().Persp(60, float64(600)/float64(600), 0.1, 50)
	tag.mvp = render.NewMvp()
	tag.initData()

	// Bind the OpenGL calls and dump some version info.
	gl.Init()
	fmt.Printf("%s %s", gl.GetString(gl.RENDERER), gl.GetString(gl.VERSION))
	fmt.Printf(" GLSL %s\n", gl.GetString(gl.SHADING_LANGUAGE_VERSION))

	// Gather the one scene into this one vertex array object.
	gl.GenVertexArrays(1, &tag.vao)
	gl.BindVertexArray(tag.vao)

	// create shaders
	tag.initShader()
	gl.UseProgram(tag.shaders)

	// vertex data.
	var vbuff uint32
	gl.GenBuffers(1, &vbuff)
	gl.BindBuffer(gl.ARRAY_BUFFER, vbuff)
	gl.BufferData(gl.ARRAY_BUFFER, int64(len(tag.verticies)*4), gl.Pointer(&(tag.verticies[0])), gl.STATIC_DRAW)
	vattr := uint32(gl.GetAttribLocation(tag.shaders, "in_v"))
	gl.EnableVertexAttribArray(vattr)
	gl.VertexAttribPointer(vattr, 3, gl.FLOAT, false, 0, 0)

	// colour data.
	var cbuff uint32
	gl.GenBuffers(1, &cbuff)
	gl.BindBuffer(gl.ARRAY_BUFFER, cbuff)
	gl.BufferData(gl.ARRAY_BUFFER, int64(len(tag.colour)*4), gl.Pointer(&(tag.colour[0])), gl.STATIC_DRAW)
	cattr := uint32(gl.GetAttribLocation(tag.shaders, "in_c"))
	gl.EnableVertexAttribArray(cattr)
	gl.VertexAttribPointer(cattr, 4, gl.FLOAT, false, 0, 0)

	// faces data.
	var ebuff uint32
	gl.GenBuffers(1, &ebuff)
	gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, ebuff)
	gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, int64(len(tag.faces)), gl.Pointer(&(tag.faces[0])), gl.STATIC_DRAW)

	// set some state that doesn't need to change during drawing.
	gl.ClearColor(0.0, 0.0, 0.0, 1.0)
	gl.Enable(gl.CULL_FACE)
	gl.CullFace(gl.BACK)
}