forked from tedsta/gosfml
/
rendertarget.go
338 lines (277 loc) · 8.13 KB
/
rendertarget.go
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package sf
import (
"github.com/go-gl/gl"
)
const vertexCacheSize = 4
type BlendMode uint8
const (
BlendAlpha BlendMode = iota // Pixel = Source * Source.a + Dest * (1 - Source.a)
BlendAdd // Pixel = Source + Dest
BlendMultiply // Pixel = Source * Dest
BlendNone /// Pixel = Source
)
// Omg badass render times
type PrimitiveType byte
const (
Points PrimitiveType = iota
Lines
LineStrip
Triangles
TriangleStrip
TriangleFan
Quads
)
type RenderStates struct {
BlendMode BlendMode // Blending mode
Transform Transform // Transform
Texture *Texture // Textures
//Shader *Shader // Shader
}
type RenderTarget struct {
Size Vector2
view *View
defaultView *View
// Cache
glStatesSet bool // Are our internal GL states set yet?
viewChanged bool // Has the current view changed since last draw?
lastBlendMode BlendMode // Cached blending mode
lastTextureId uint64 // Cached texture
useVertexCache bool // Did we previously use the vertex cache?
vertexCache [vertexCacheSize]Vertex // Pre-transformed vertices cache
}
func NewRenderTarget(size Vector2) *RenderTarget {
rt := &RenderTarget{Size: size}
rt.glStatesSet = false
rt.defaultView = NewView()
rt.defaultView.Reset(Rect{0, 0, rt.Size.X, rt.Size.Y})
rt.view = NewView()
*(rt.view) = *(rt.defaultView)
return rt
}
func (r *RenderTarget) Clear(color Color) {
gl.ClearColor(gl.GLclampf(color.R/255), gl.GLclampf(color.G/255), gl.GLclampf(color.B/255), gl.GLclampf(color.A/255))
gl.Clear(gl.COLOR_BUFFER_BIT)
}
func (r *RenderTarget) SetView(view View) {
*(r.view) = view
r.viewChanged = true
}
func (r *RenderTarget) View() View {
return *(r.view)
}
func (r *RenderTarget) DefaultView() View {
return *(r.defaultView)
}
func (r *RenderTarget) Viewport(view *View) Rect {
w := r.Size.X
h := r.Size.Y
viewport := view.Viewport()
return Rect{0.5 + w*viewport.Left,
0.5 + h*viewport.Top,
w * viewport.W,
h * viewport.H}
}
func (r *RenderTarget) Render(verts []Vertex, primType PrimitiveType, states RenderStates) {
// Nothing to draw?
if len(verts) == 0 {
return
}
// First set the persistent OpenGL states if it's the very first call
if !r.glStatesSet {
r.resetGlStates()
}
// Check if the vertex count is low enough so that we can pre-transform them
// TODO: Fix vertex cache
useVertexCache := /*len(verts) <= vertexCacheSize*/ false
if useVertexCache {
// Pre-transform the vertices and store them into the vertex cache
for i := 0; i < len(verts); i++ {
r.vertexCache[i].Pos = states.Transform.TransformPoint(verts[i].Pos)
r.vertexCache[i].Color = verts[i].Color
r.vertexCache[i].TexCoords = verts[i].TexCoords
}
// Since vertices are transformed, we must use an identity transform to render them
if !r.useVertexCache {
r.applyTransform(IdentityTransform())
}
} else {
r.applyTransform(states.Transform)
}
// Apply the view
if r.viewChanged {
r.applyCurrentView()
}
// Apply the blend mode
if states.BlendMode != r.lastBlendMode {
//r.applyBlendMode(states.BlendMode)
}
// Apply the texture
var textureId uint64
if states.Texture != nil {
textureId = states.Texture.cacheId
}
if textureId != r.lastTextureId {
r.applyTexture(states.Texture)
}
// Apply the shader
// TODO
/*if states.shader {
applyShader(states.shader);
}*/
// If we pre-transform the vertices, we must use our internal vertex cache
if useVertexCache {
// ... and if we already used it previously, we don't need to set the pointers again
if !r.useVertexCache {
verts = r.vertexCache[:]
} else {
verts = nil
}
}
// #########################################
if len(verts) > 0 {
// Find the OpenGL primitive type
modes := [...]gl.GLenum{gl.POINTS, gl.LINES, gl.LINE_STRIP, gl.TRIANGLES,
gl.TRIANGLE_STRIP, gl.TRIANGLE_FAN, gl.QUADS}
mode := modes[primType]
gl.Begin(mode)
for i, _ := range verts {
gl.TexCoord2f(verts[i].TexCoords.X, verts[i].TexCoords.Y)
gl.Color4f(verts[i].Color.R/255, verts[i].Color.G/255,
verts[i].Color.B/255, verts[i].Color.A/255)
gl.Vertex2f(verts[i].Pos.X, verts[i].Pos.Y)
}
gl.End()
}
// #########################################
// Setup the pointers to the vertices' components
/*if len(verts) > 0 {
vData := make([]Vector2, len(verts))
//cData := make([]byte, len(verts))
tData := make([]Vector2, len(verts))
for i, _ := range verts {
vData[i] = verts[i].Pos
//cData[i] = verts[i].Color
tData[i] = verts[i].TexCoords
}
//const char* data = reinterpret_cast<const char*>(vertices);
gl.VertexPointer(2, gl.FLOAT, 0, vData)
//gl.ColorPointer(4, gl.UNSIGNED_BYTE, unsafe.Sizeof(Vertex), cData))
gl.TexCoordPointer(2, gl.FLOAT, 0, tData)
}
// Find the OpenGL primitive type
modes := [...]gl.GLenum{gl.POINTS, gl.LINES, gl.LINE_STRIP, gl.TRIANGLES,
gl.TRIANGLE_STRIP, gl.TRIANGLE_FAN, gl.QUADS}
mode := modes[primType]
// Draw the primitives
gl.DrawArrays(mode, 0, len(verts))*/
// Unbind the shader, if any
// TODO
/*if (states.shader) {
r.applyShader(nil)
}*/
// Update the cache
r.useVertexCache = useVertexCache
}
func (r *RenderTarget) pushGlStates() {
gl.PushClientAttrib(gl.CLIENT_ALL_ATTRIB_BITS)
gl.PushAttrib(gl.ALL_ATTRIB_BITS)
gl.MatrixMode(gl.MODELVIEW)
gl.PushMatrix()
gl.MatrixMode(gl.PROJECTION)
gl.PushMatrix()
gl.MatrixMode(gl.TEXTURE)
gl.PushMatrix()
r.resetGlStates()
}
func (r *RenderTarget) popGlStates() {
gl.MatrixMode(gl.PROJECTION)
gl.PopMatrix()
gl.MatrixMode(gl.MODELVIEW)
gl.PopMatrix()
gl.MatrixMode(gl.TEXTURE)
gl.PopMatrix()
gl.PopClientAttrib()
gl.PopAttrib()
}
func (r *RenderTarget) resetGlStates() {
// Define the default OpenGL states
gl.Disable(gl.CULL_FACE)
gl.Disable(gl.LIGHTING)
gl.Disable(gl.DEPTH_TEST)
gl.Disable(gl.ALPHA_TEST)
gl.Enable(gl.TEXTURE_2D)
gl.Enable(gl.BLEND)
gl.MatrixMode(gl.MODELVIEW)
gl.EnableClientState(gl.VERTEX_ARRAY)
gl.EnableClientState(gl.COLOR_ARRAY)
gl.EnableClientState(gl.TEXTURE_COORD_ARRAY)
r.glStatesSet = true
// Apply the default SFML states
r.applyBlendMode(BlendAlpha)
r.applyTransform(IdentityTransform())
r.applyTexture(nil)
/*if (Shader::isAvailable()){
r.applyShader(nil)
}*/
r.useVertexCache = false
// Set the default view
r.SetView(r.View())
}
func (r *RenderTarget) applyCurrentView() {
// Set the viewport
viewport := r.Viewport(r.view)
top := r.Size.Y - (viewport.Top + viewport.H)
gl.Viewport(int(viewport.Left), int(top), int(viewport.W), int(viewport.H))
mat := r.view.Transform().Matrix
// Set the projection matrix
gl.MatrixMode(gl.PROJECTION)
gl.LoadMatrixf(&mat)
// Go back to model-view mode
gl.MatrixMode(gl.MODELVIEW)
r.viewChanged = false
}
func (r *RenderTarget) applyBlendMode(mode BlendMode) {
switch mode {
// glBlendFuncSeparateEXT is used when available to avoid an incorrect alpha value when the target
// is a RenderTexture -- in this case the alpha value must be written directly to the target buffer
// Alpha blending
default:
gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
case BlendAlpha:
/*if (GLEW_EXT_blend_func_separate) {
glBlendFuncSeparateEXT(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA, gl.ONE, gl.ONE_MINUS_SRC_ALPHA)
} else {*/
gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
//}
// Additive blending
case BlendAdd:
/*if GLEW_EXT_blend_func_separate {
gl.BlendFuncSeparateEXT(gl.SRC_ALPHA, gl.ONE, gl.ONE, gl.ONE)
} else {*/
gl.BlendFunc(gl.SRC_ALPHA, gl.ONE)
//}
// Multiplicative blending
case BlendMultiply:
gl.BlendFunc(gl.DST_COLOR, gl.ZERO)
// No blending
case BlendNone:
gl.BlendFunc(gl.ONE, gl.ZERO)
}
r.lastBlendMode = mode
}
func (r *RenderTarget) applyTransform(transform Transform) {
// No need to call glMatrixMode(gl.MODELVIEW), it is always the
// current mode (for optimization purpose, since it's the most used)
gl.LoadMatrixf(&transform.Matrix)
}
func (r *RenderTarget) applyTexture(texture *Texture) {
texture.Bind(CoordPixels)
if texture != nil {
r.lastTextureId = texture.cacheId
} else {
r.lastTextureId = 0
}
}
/*func (r *RenderTarget) applyShader(shader *Shader) {
Shader::bind(shader);
}*/