252 lines
8.3 KiB
Go
252 lines
8.3 KiB
Go
package backend
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import (
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_ "embed"
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"edgaru089.ml/go/gl01/internal/igwrap"
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"edgaru089.ml/go/gl01/internal/render"
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"github.com/go-gl/gl/all-core/gl"
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"github.com/go-gl/glfw/v3.3/glfw"
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"github.com/go-gl/mathgl/mgl32"
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"github.com/inkyblackness/imgui-go/v4"
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)
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//go:embed shader.vert
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var vertex string
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//go:embed shader.frag
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var fragment string
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var (
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shader *render.Shader
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texture *render.Texture
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vbo, elem uint32
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attribPosition, attribUV, attribColor uint32
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)
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func renderInit() {
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// Backup GL state
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var lastTexture int32
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var lastArrayBuffer int32
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var lastVertexArray int32
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gl.GetIntegerv(gl.TEXTURE_BINDING_2D, &lastTexture)
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gl.GetIntegerv(gl.ARRAY_BUFFER_BINDING, &lastArrayBuffer)
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gl.GetIntegerv(gl.VERTEX_ARRAY_BINDING, &lastVertexArray)
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var err error
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shader, err = render.NewShader(vertex, fragment)
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if err != nil {
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panic("igwrap.renderInit(): " + err.Error())
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}
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gl.BindFragDataLocation(shader.Handle(), 0, gl.Str("outputColor\x00"))
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gl.GenBuffers(1, &vbo)
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gl.GenBuffers(1, &elem)
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CreateFontsTexture()
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shader.SetUniformTexture("tex", texture)
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attribPosition = uint32(gl.GetAttribLocation(shader.Handle(), gl.Str("pos\x00")))
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attribUV = uint32(gl.GetAttribLocation(shader.Handle(), gl.Str("uv\x00")))
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attribColor = uint32(gl.GetAttribLocation(shader.Handle(), gl.Str("color\x00")))
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// Restore modified GL state
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gl.BindTexture(gl.TEXTURE_2D, uint32(lastTexture))
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gl.BindBuffer(gl.ARRAY_BUFFER, uint32(lastArrayBuffer))
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gl.BindVertexArray(uint32(lastVertexArray))
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}
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func CreateFontsTexture() {
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// build the texture atlas
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io := imgui.CurrentIO()
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image := io.Fonts().TextureDataAlpha8()
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var lastTexture int32
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gl.GetIntegerv(gl.TEXTURE_BINDING_2D, &lastTexture)
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if texture != nil {
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texture.Free()
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}
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texture = render.NewTexture()
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tex := texture.Handle()
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gl.BindTexture(gl.TEXTURE_2D, tex)
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gl.TexImage2D(
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gl.TEXTURE_2D,
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0,
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gl.RED,
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int32(image.Width),
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int32(image.Height),
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0,
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gl.RED,
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gl.UNSIGNED_BYTE,
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image.Pixels,
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)
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io.Fonts().SetTextureID(imgui.TextureID(tex))
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igwrap.SetTextureFlag(tex, igwrap.TextureFlag_ImGUIFont)
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gl.BindTexture(gl.TEXTURE_2D, uint32(lastTexture))
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}
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func Render(win *glfw.Window) {
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displayWidth, displayHeight := win.GetSize()
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fbWidth, fbHeight := win.GetFramebufferSize()
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imgui.Render()
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draw := imgui.RenderedDrawData()
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draw.ScaleClipRects(imgui.Vec2{
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X: float32(fbWidth) / float32(displayWidth),
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Y: float32(fbHeight) / float32(displayHeight),
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})
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// Backup GL state
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var lastActiveTexture int32
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gl.GetIntegerv(gl.ACTIVE_TEXTURE, &lastActiveTexture)
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gl.ActiveTexture(gl.TEXTURE0)
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var lastProgram int32
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gl.GetIntegerv(gl.CURRENT_PROGRAM, &lastProgram)
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var lastTexture int32
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gl.GetIntegerv(gl.TEXTURE_BINDING_2D, &lastTexture)
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var lastSampler int32
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gl.GetIntegerv(gl.SAMPLER_BINDING, &lastSampler)
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var lastArrayBuffer int32
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gl.GetIntegerv(gl.ARRAY_BUFFER_BINDING, &lastArrayBuffer)
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var lastElementArrayBuffer int32
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gl.GetIntegerv(gl.ELEMENT_ARRAY_BUFFER_BINDING, &lastElementArrayBuffer)
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var lastVertexArray int32
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gl.GetIntegerv(gl.VERTEX_ARRAY_BINDING, &lastVertexArray)
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var lastPolygonMode [2]int32
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gl.GetIntegerv(gl.POLYGON_MODE, &lastPolygonMode[0])
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var lastViewport [4]int32
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gl.GetIntegerv(gl.VIEWPORT, &lastViewport[0])
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var lastScissorBox [4]int32
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gl.GetIntegerv(gl.SCISSOR_BOX, &lastScissorBox[0])
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var lastBlendSrcRgb int32
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gl.GetIntegerv(gl.BLEND_SRC_RGB, &lastBlendSrcRgb)
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var lastBlendDstRgb int32
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gl.GetIntegerv(gl.BLEND_DST_RGB, &lastBlendDstRgb)
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var lastBlendSrcAlpha int32
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gl.GetIntegerv(gl.BLEND_SRC_ALPHA, &lastBlendSrcAlpha)
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var lastBlendDstAlpha int32
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gl.GetIntegerv(gl.BLEND_DST_ALPHA, &lastBlendDstAlpha)
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var lastBlendEquationRgb int32
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gl.GetIntegerv(gl.BLEND_EQUATION_RGB, &lastBlendEquationRgb)
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var lastBlendEquationAlpha int32
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gl.GetIntegerv(gl.BLEND_EQUATION_ALPHA, &lastBlendEquationAlpha)
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lastEnableBlend := gl.IsEnabled(gl.BLEND)
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lastEnableCullFace := gl.IsEnabled(gl.CULL_FACE)
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lastEnableDepthTest := gl.IsEnabled(gl.DEPTH_TEST)
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lastEnableScissorTest := gl.IsEnabled(gl.SCISSOR_TEST)
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// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
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gl.Enable(gl.BLEND)
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gl.BlendEquation(gl.FUNC_ADD)
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gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
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gl.Disable(gl.CULL_FACE)
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gl.Disable(gl.DEPTH_TEST)
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gl.Enable(gl.SCISSOR_TEST)
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gl.PolygonMode(gl.FRONT_AND_BACK, gl.FILL)
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// Setup viewport, orthographic projection matrix
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// Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right).
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// DisplayMin is typically (0,0) for single viewport apps.
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gl.Viewport(0, 0, int32(fbWidth), int32(fbHeight))
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orthoProjection := mgl32.Mat4{
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2.0 / float32(displayWidth), 0.0, 0.0, 0.0,
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0.0, 2.0 / float32(-displayHeight), 0.0, 0.0,
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0.0, 0.0, -1.0, 0.0,
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-1.0, 1.0, 0.0, 1.0,
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}
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shader.BindTextures()
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shader.UseProgram()
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shader.SetUniformMat4("projection", orthoProjection)
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gl.BindSampler(0, 0) // Rely on combined texture/sampler state.
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// Recreate the VAO every time
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// (This is to easily allow multiple GL contexts. VAO are not shared among GL contexts, and
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// we don't track creation/deletion of windows so we don't have an obvious key to use to cache them.)
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var vao uint32
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gl.GenVertexArrays(1, &vao)
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gl.BindVertexArray(vao)
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gl.BindBuffer(gl.ARRAY_BUFFER, vbo)
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gl.EnableVertexAttribArray(uint32(attribPosition))
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gl.EnableVertexAttribArray(uint32(attribUV))
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gl.EnableVertexAttribArray(uint32(attribColor))
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vertexSize, vertexOffsetPos, vertexOffsetUv, vertexOffsetCol := imgui.VertexBufferLayout()
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gl.VertexAttribPointerWithOffset(uint32(attribPosition), 2, gl.FLOAT, false, int32(vertexSize), uintptr(vertexOffsetPos))
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gl.VertexAttribPointerWithOffset(uint32(attribUV), 2, gl.FLOAT, false, int32(vertexSize), uintptr(vertexOffsetUv))
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gl.VertexAttribPointerWithOffset(uint32(attribColor), 4, gl.UNSIGNED_BYTE, true, int32(vertexSize), uintptr(vertexOffsetCol))
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indexSize := imgui.IndexBufferLayout()
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drawType := gl.UNSIGNED_SHORT
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const bytesPerUint32 = 4
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if indexSize == bytesPerUint32 {
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drawType = gl.UNSIGNED_INT
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}
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// Draw
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for _, list := range draw.CommandLists() {
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var indexBufferOffset uintptr
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vertexBuffer, vertexBufferSize := list.VertexBuffer()
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gl.BindBuffer(gl.ARRAY_BUFFER, vbo)
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gl.BufferData(gl.ARRAY_BUFFER, vertexBufferSize, vertexBuffer, gl.STREAM_DRAW)
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indexBuffer, indexBufferSize := list.IndexBuffer()
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gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, elem)
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gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, indexBufferSize, indexBuffer, gl.STREAM_DRAW)
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for _, cmd := range list.Commands() {
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if cmd.HasUserCallback() {
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cmd.CallUserCallback(list)
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} else {
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shader.SetUniformInt("flags", int32(igwrap.GetTextureFlag(uint32(cmd.TextureID()))))
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gl.BindTexture(gl.TEXTURE_2D, uint32(cmd.TextureID()))
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clipRect := cmd.ClipRect()
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gl.Scissor(int32(clipRect.X), int32(fbHeight)-int32(clipRect.W), int32(clipRect.Z-clipRect.X), int32(clipRect.W-clipRect.Y))
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gl.DrawElementsWithOffset(gl.TRIANGLES, int32(cmd.ElementCount()), uint32(drawType), indexBufferOffset)
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}
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indexBufferOffset += uintptr(cmd.ElementCount() * indexSize)
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}
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}
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gl.DeleteVertexArrays(1, &vao)
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// Restore modified GL state
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gl.UseProgram(uint32(lastProgram))
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gl.BindTexture(gl.TEXTURE_2D, uint32(lastTexture))
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gl.BindSampler(0, uint32(lastSampler))
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gl.ActiveTexture(uint32(lastActiveTexture))
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gl.BindVertexArray(uint32(lastVertexArray))
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gl.BindBuffer(gl.ARRAY_BUFFER, uint32(lastArrayBuffer))
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gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, uint32(lastElementArrayBuffer))
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gl.BlendEquationSeparate(uint32(lastBlendEquationRgb), uint32(lastBlendEquationAlpha))
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gl.BlendFuncSeparate(uint32(lastBlendSrcRgb), uint32(lastBlendDstRgb), uint32(lastBlendSrcAlpha), uint32(lastBlendDstAlpha))
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if lastEnableBlend {
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gl.Enable(gl.BLEND)
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} else {
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gl.Disable(gl.BLEND)
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}
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if lastEnableCullFace {
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gl.Enable(gl.CULL_FACE)
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} else {
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gl.Disable(gl.CULL_FACE)
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}
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if lastEnableDepthTest {
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gl.Enable(gl.DEPTH_TEST)
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} else {
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gl.Disable(gl.DEPTH_TEST)
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}
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if lastEnableScissorTest {
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gl.Enable(gl.SCISSOR_TEST)
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} else {
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gl.Disable(gl.SCISSOR_TEST)
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}
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gl.PolygonMode(gl.FRONT_AND_BACK, uint32(lastPolygonMode[0]))
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gl.Viewport(lastViewport[0], lastViewport[1], lastViewport[2], lastViewport[3])
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gl.Scissor(lastScissorBox[0], lastScissorBox[1], lastScissorBox[2], lastScissorBox[3])
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}
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