Py API Docs: Another example for offscreen rendering

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Jacques Lucke 2018-11-12 17:17:59 +01:00
parent 583bc70435
commit 406452ec5d
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"""
Generate a texture using Offscreen Rendering
--------------------------------------------
1. Create an :class:`gpu.types.GPUOffScreen` object.
2. Draw some circles into it.
3. Make a new shader for drawing a planar texture in 3D.
4. Draw the generated texture using the new shader.
"""
import bpy
import gpu
import bgl
from mathutils import Matrix
from gpu_extras.batch import batch_for_shader
from gpu_extras.presets import draw_circle_2d
# Create and fill offscreen
##########################################
offscreen = gpu.types.GPUOffScreen(512, 512)
offscreen.bind()
try:
bgl.glClear(bgl.GL_COLOR_BUFFER_BIT)
with gpu.matrix.push_pop():
gpu.matrix.load_matrix(Matrix.Identity(4))
gpu.matrix.load_projection_matrix(Matrix.Identity(4))
amount = 10
for i in range(-amount, amount + 1):
x_pos = i / amount
draw_circle_2d((x_pos, 0.0), (1, 1, 1, 1), 0.5, 200)
finally:
offscreen.unbind()
# Drawing the generated texture in 3D space
#############################################
vertex_shader = '''
uniform mat4 modelMatrix;
uniform mat4 viewProjectionMatrix;
in vec2 position;
in vec2 uv;
out vec2 uvInterp;
void main()
{
uvInterp = uv;
gl_Position = viewProjectionMatrix * modelMatrix * vec4(position, 0.0, 1.0);
}
'''
fragment_shader = '''
uniform sampler2D image;
in vec2 uvInterp;
void main()
{
gl_FragColor = texture(image, uvInterp);
}
'''
shader = gpu.types.GPUShader(vertex_shader, fragment_shader)
batch = batch_for_shader(shader, 'TRI_FAN',
{"position" : ((-1, -1), (1, -1), (1, 1), (-1, 1)),
"uv" : ((0, 0), (1, 0), (1, 1), (0, 1))})
def draw():
bgl.glActiveTexture(bgl.GL_TEXTURE0)
bgl.glBindTexture(bgl.GL_TEXTURE_2D, offscreen.color_texture)
shader.bind()
shader.uniform_float("modelMatrix", Matrix.Translation((1, 2, 3)) @ Matrix.Scale(3, 4))
shader.uniform_float("viewProjectionMatrix", bpy.context.region_data.perspective_matrix)
shader.uniform_float("image", 0)
batch.draw(shader)
bpy.types.SpaceView3D.draw_handler_add(draw, (), 'WINDOW', 'POST_VIEW')