render: move render_world_helper, remove chunks drawn behind view

2022-01-27 01:09:45 +08:00
parent d8df67bc20
commit 7b6c16789c
11 changed files with 257 additions and 56 deletions
--- a/internal/render/screenquad.go
+++ b/internal/render/screenquad.go
@@ -0,0 +1,122 @@
+package render
+
+import (
+	_ "embed"
+	"unsafe"
+
+	"edgaru089.ml/go/gl01/internal/util/itype"
+	"github.com/go-gl/gl/all-core/gl"
+)
+
+var (
+	screenQuadVerts = []float32{
+		-1, -1,
+		0, 0,
+		1, -1,
+		1, 0,
+		1, 1,
+		1, 1,
+		-1, -1,
+		0, 0,
+		1, 1,
+		1, 1,
+		-1, 1,
+		0, 1,
+	}
+	screenQuadVAO uint32
+	screenQuadVBO uint32
+
+	drawTextureShader *Shader // Shader for dumping textures to screen
+)
+
+func initScreenQuad() {
+	gl.GenBuffers(1, &screenQuadVBO)
+	gl.BindBuffer(gl.ARRAY_BUFFER, screenQuadVBO)
+	gl.BufferData(gl.ARRAY_BUFFER, int(unsafe.Sizeof(float32(0)))*len(screenQuadVerts), gl.Ptr(screenQuadVerts), gl.STATIC_DRAW)
+
+	gl.GenVertexArrays(1, &screenQuadVAO)
+	gl.BindVertexArray(screenQuadVAO)
+
+	gl.VertexAttribPointer(0, 2, gl.FLOAT, false, int32(4*unsafe.Sizeof(float32(0))), gl.PtrOffset(0))
+	gl.VertexAttribPointer(1, 2, gl.FLOAT, false, int32(4*unsafe.Sizeof(float32(0))), gl.PtrOffset(int(2*unsafe.Sizeof(float32(0)))))
+	gl.EnableVertexAttribArray(0)
+	gl.EnableVertexAttribArray(1)
+}
+
+// DrawScreenQuad draws a Quad covering the entire screen with the current binding shader.
+//
+// Attribute: (location=0) vert:     [ -1.0 --> 1.0]
+//            (location=1) texCoord: [ 0    --> 1]
+func DrawScreenQuad() {
+	if screenQuadVAO == 0 {
+		initScreenQuad()
+	}
+
+	gl.Disable(gl.DEPTH_TEST)
+	gl.Disable(gl.CULL_FACE)
+	gl.BindVertexArray(screenQuadVAO)
+	gl.DrawArrays(gl.TRIANGLES, 0, 6)
+}
+
+// DrawTextureChannels specifies the channels in RGBA to be drawn.
+type DrawTextureChannels int
+
+const (
+	DrawTextureChannels_R DrawTextureChannels = 1 << iota
+	DrawTextureChannels_G
+	DrawTextureChannels_B
+	DrawTextureChannels_A
+)
+
+var (
+	//go:embed drawtexture.vert
+	drawTextureShaderVert string
+	//go:embed drawtexture.frag
+	drawTextureShaderFrag string
+)
+
+func initDrawTexture() {
+	var err error
+	drawTextureShader, err = NewShader(drawTextureShaderVert, drawTextureShaderFrag)
+	if err != nil {
+		panic(err)
+	}
+
+	gl.BindFragDataLocation(drawTextureShader.Handle(), 0, gl.Str("outputColor\x00"))
+}
+
+// DrawTexture dumps the contents of a Texture onto the portion of the screen.
+// It disables depth test and cull face.
+//
+// onScreen is specified in [-1, 1] size.
+//
+// If only one channel is specified, that channel is drawn in black and white.
+// Otherwise, R/G/B are drawn in their specified channels and A is ignored.
+//
+// The texture values from vauleRange is mapped to [0, 1] linearly.
+//
+// TODO: This does not work. Maybe something wrong with the shaders or blending
+func DrawTexture(texture uint32, onScreen itype.Rectf, channels DrawTextureChannels, valueMin, valueMax float32) {
+	if screenQuadVAO == 0 {
+		initScreenQuad()
+	}
+	if drawTextureShader == nil {
+		initDrawTexture()
+	}
+
+	drawTextureShader.UseProgram()
+
+	drawTextureShader.SetUniformVec2f("onScreenPos", onScreen.MinPoint())
+	drawTextureShader.SetUniformVec2f("onScreenSize", onScreen.Size())
+	drawTextureShader.SetUniformFloat("valueMin", valueMin)
+	drawTextureShader.SetUniformFloat("valueMax", valueMax)
+	drawTextureShader.SetUniformInt("channels", int32(channels))
+	drawTextureShader.SetUniformTextureHandle("tex", texture)
+
+	drawTextureShader.BindTextures()
+
+	gl.Disable(gl.DEPTH_TEST)
+	gl.Disable(gl.CULL_FACE)
+	gl.BindVertexArray(screenQuadVAO)
+	gl.DrawArrays(gl.TRIANGLES, 0, 6)
+}