func (polyline *polyLine) drawTriangles(is_looping bool) {
var overdraw []mgl32.Vec2
if polyline.overdraw {
overdraw = polyline.renderOverdraw(is_looping)
}
numindices := int(math.Max(float64(len(polyline.vertices)/4), float64(len(overdraw)/4)))
indices := newAltQuadIndices(numindices)
prepareDraw(nil)
bindTexture(gl_state.defaultTexture)
useVertexAttribArrays(attribflag_pos)
gl.VertexAttribPointer(attrib_pos, 2, gl.FLOAT, false, 0, gl.Ptr(polyline.vertices))
gl.DrawElements(gl.TRIANGLES, (len(polyline.vertices)/4)*6, gl.UNSIGNED_SHORT, gl.Ptr(indices))
if polyline.overdraw {
c := GetColor()
colors := polyline.generateColorArray(len(overdraw), c)
useVertexAttribArrays(attribflag_pos | attribflag_color)
gl.VertexAttribPointer(attrib_color, 4, gl.UNSIGNED_BYTE, true, 0, gl.Ptr(colors))
gl.VertexAttribPointer(attrib_pos, 2, gl.FLOAT, false, 0, gl.Ptr(overdraw))
gl.DrawElements(gl.TRIANGLES, (len(overdraw)/4)*6, gl.UNSIGNED_SHORT, gl.Ptr(indices))
SetColorC(c)
}
indices.Release()
}
// drawv will take in verticies from the public draw calls and draw the texture
// with the verticies and the model matrix
func (texture *Texture) drawv(model *mgl32.Mat4, vertices []float32) {
prepareDraw(model)
bindTexture(texture.getHandle())
useVertexAttribArrays(attribflag_pos | attribflag_texcoord)
gl.VertexAttribPointer(attrib_pos, 2, gl.FLOAT, false, 4*4, gl.Ptr(vertices))
gl.VertexAttribPointer(attrib_texcoord, 2, gl.FLOAT, false, 4*4, gl.Ptr(&vertices[2]))
gl.DrawArrays(gl.TRIANGLE_STRIP, 0, 4)
}
// Point will draw a point on the screen at x, y position. The size of the point
// is dependant on the point size set with SetPointSize.
func Point(x, y float32) {
prepareDraw(nil)
bindTexture(gl_state.defaultTexture)
useVertexAttribArrays(attribflag_pos)
gl.VertexAttribPointer(attrib_pos, 2, gl.FLOAT, false, 0, gl.Ptr([]float32{x, y}))
gl.DrawArrays(gl.POINTS, 0, 1)
}
// Circlep will draw a circle at x, y with a radius as specified.
// radiusx and radiusy will specify how much the width will be along those axis
// points specifies how many points should be generated in the arc.
// If it is lower it will look jagged. If it is higher it will hit performace.
// The drawmode specifies either a fill or line draw
func Ellipsep(mode DrawMode, x, y, radiusx, radiusy float32, points int) {
two_pi := math.Pi * 2.0
if points <= 0 {
points = 1
}
angle_shift := float32(two_pi) / float32(points)
phi := float32(0.0)
coords := make([]float32, 2*(points+1))
for i := 0; i < points; i++ {
phi += angle_shift
coords[2*i+0] = x + radiusx*float32(math.Cos(float64(phi)))
coords[2*i+1] = y + radiusy*float32(math.Sin(float64(phi)))
}
coords[2*points+0] = coords[0]
coords[2*points+1] = coords[1]
if mode == LINE {
PolyLine(coords)
} else {
prepareDraw(nil)
bindTexture(gl_state.defaultTexture)
useVertexAttribArrays(attribflag_pos)
gl.VertexAttribPointer(attrib_pos, 2, gl.FLOAT, false, 0, gl.Ptr(coords))
gl.DrawArrays(gl.TRIANGLE_FAN, 0, len(coords)/2-1)
}
}
func (buffer *vertexBuffer) bufferStatic() {
if buffer.modified_size == 0 {
return
}
// Upload the mapped data to the buffer.
gl.BufferSubData(gl.ARRAY_BUFFER, buffer.modified_offset*4, buffer.modified_size*4, gl.Ptr(&buffer.data[buffer.modified_offset]))
}
func (buffer *vertexBuffer) loadVolatile() bool {
buffer.vbo = gl.CreateBuffer()
buffer.bind()
defer buffer.unbind()
gl.BufferData(gl.ARRAY_BUFFER, len(buffer.data)*4, gl.Ptr(buffer.data), uint32(buffer.usage))
return true
}
func (polyline *polyLine) drawTriangleStrip(is_looping bool) {
prepareDraw(nil)
bindTexture(gl_state.defaultTexture)
useVertexAttribArrays(attribflag_pos)
gl.VertexAttribPointer(attrib_pos, 2, gl.FLOAT, false, 0, gl.Ptr(polyline.vertices))
gl.DrawArrays(gl.TRIANGLE_STRIP, 0, len(polyline.vertices))
if polyline.overdraw { // prepare colors:
c := GetColor()
overdraw := polyline.renderOverdraw(is_looping)
colors := polyline.generateColorArray(len(overdraw), c)
useVertexAttribArrays(attribflag_pos | attribflag_color)
gl.VertexAttribPointer(attrib_color, 4, gl.UNSIGNED_BYTE, true, 0, gl.Ptr(colors))
gl.VertexAttribPointer(attrib_pos, 2, gl.FLOAT, false, 0, gl.Ptr(overdraw))
gl.DrawArrays(gl.TRIANGLE_STRIP, 0, len(overdraw))
SetColorC(c)
}
}
// Polygon will draw a closed polygon with an array in the form of x1, y1, x2, y2, x3, y3, ..... xn, yn
// The drawmode specifies either a fill or line draw
func Polygon(mode DrawMode, coords []float32) {
coords = append(coords, coords[0], coords[1])
if mode == LINE {
PolyLine(coords)
} else {
prepareDraw(nil)
bindTexture(gl_state.defaultTexture)
useVertexAttribArrays(attribflag_pos)
gl.VertexAttribPointer(attrib_pos, 2, gl.FLOAT, false, 0, gl.Ptr(coords))
gl.DrawArrays(gl.TRIANGLE_FAN, 0, len(coords)/2-1)
}
}
// Set the 'default' texture (id 0) as a repeating white pixel. Otherwise,
// texture2D calls inside a shader would return black when drawing graphics
// primitives, which would create the need to use different "passthrough"
// shaders for untextured primitives vs images.
func createDefaultTexture() {
gl_state.defaultTexture = gl.CreateTexture()
bindTexture(gl_state.defaultTexture)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT)
pix := []byte{255, 255, 255, 255}
gl.TexImage2D(gl.TEXTURE_2D, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, gl.Ptr(pix))
}
// Arcp is like Arc except that you can define how many points you want to generate
// the arc.
// If it is lower it will look jagged. If it is higher it will hit performace.
// The drawmode specifies either a fill or line draw
func Arcp(mode DrawMode, x, y, radius, angle1, angle2 float32, points int) {
// Nothing to display with no points or equal angles. (Or is there with line mode?)
if points <= 0 || angle1 == angle2 {
return
}
// Oh, you want to draw a circle?
if math.Abs(float64(angle1-angle2)) >= (2.0 * math.Pi) {
Circlep(mode, x, y, radius, points)
return
}
angle_shift := (angle2 - angle1) / float32(points)
// Bail on precision issues.
if angle_shift == 0.0 {
return
}
phi := angle1
num_coords := (points + 3) * 2
coords := make([]float32, num_coords)
coords[0] = x
coords[num_coords-2] = x
coords[1] = y
coords[num_coords-1] = y
for i := 0; i <= points; i++ {
phi = phi + angle_shift
coords[2*(i+1)] = x + radius*float32(math.Cos(float64(phi)))
coords[2*(i+1)+1] = y + radius*float32(math.Sin(float64(phi)))
}
if mode == LINE {
PolyLine(coords)
} else {
prepareDraw(nil)
bindTexture(gl_state.defaultTexture)
useVertexAttribArrays(attribflag_pos)
gl.VertexAttribPointer(attrib_pos, 2, gl.FLOAT, false, 0, gl.Ptr(coords))
gl.DrawArrays(gl.TRIANGLE_FAN, 0, len(coords)/2-1)
}
}
// newImageTexture will generate a texture from an image. It will automatically
// upload the image data to the texture.
func newImageTexture(img image.Image, mipmaps bool) (*Texture, error) {
bounds := img.Bounds()
new_texture := newTexture(int32(bounds.Dx()), int32(bounds.Dy()), mipmaps)
//generate a uniform image and upload to vram
rgba := image.NewRGBA(img.Bounds())
draw.Draw(rgba, bounds, img, image.Point{0, 0}, draw.Src)
bindTexture(new_texture.getHandle())
gl.TexImage2D(gl.TEXTURE_2D, 0, bounds.Dx(), bounds.Dy(), gl.RGBA, gl.UNSIGNED_BYTE, gl.Ptr(rgba.Pix))
if new_texture.mipmaps {
new_texture.generateMipmaps()
}
return new_texture, nil
}
func (buffer *vertexBuffer) bufferStream() {
// "orphan" current buffer to avoid implicit synchronisation on the GPU:
// http://www.seas.upenn.edu/~pcozzi/OpenGLInsights/OpenGLInsights-AsynchronousBufferTransfers.pdf
gl.BufferData(gl.ARRAY_BUFFER, len(buffer.data)*4, gl.Ptr(nil), uint32(buffer.usage))
gl.BufferData(gl.ARRAY_BUFFER, len(buffer.data)*4, gl.Ptr(buffer.data), uint32(buffer.usage))
}
func (buffer *indexBuffer) drawElementsLocal(mode uint32, offset, size int) {
gl.DrawElements(gl.Enum(mode), size, gl.UNSIGNED_INT, gl.Ptr(&buffer.data[offset]))
}