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This thread is locked; no one can reply to it.
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| Combining Allegro 5.1.8 with OpenGL culling problems |
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mind78
Member #15,802
November 2014
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I am using Allegro 5.1.8 with Msys2. I am trying to combine OpenGL and Allegro drawing, using Allegro routines to draw 2D elements in front of the 3D scene. Well, so far so good, I get it drawing all right but I am getting stuck on Backface culling. I have allegro drawing a bitmap mousepointer on top of my 3D scene (a spinning cube). I am using a single al_flip_display(), in this fashion: setupGLstuff(); while(1) I can either have no backface culling, and my 2D overlay works, or I can have backfaceculling, and my 2D overlay disappears. Anyone knows the best way to get this to work? I was thinking maybe rendering 3D to a bitmap, and then disabling backface culling again, and rendering the 2D on top of that bitmap before showing it but maybe there is a better way?
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Thomas Fjellstrom
Member #476
June 2000
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I think you want to disable culling before drawing using allegro. I'm doing that in my current project. {"name":"3FAegCS.png","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/f\/b\/fbcf87028635f4dda63ab2ea7c1bcb93.png","w":806,"h":627,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/f\/b\/fbcf87028635f4dda63ab2ea7c1bcb93"} -- |
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mind78
Member #15,802
November 2014
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I am trying too. No luck, for instance, if I change the above scenario to this: setupGLstuff(); while(1) Allegro drawing works, but the GL stuff gets drawn without culling as well. [Edit:] Hold on, I just think I realized how truly retarded I should feel right now. Let me test something.
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Thomas Fjellstrom
Member #476
June 2000
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This is basically my code: 1// main loop:
2
3 ALLEGRO_STATE state;
4 al_store_state(&state, ALLEGRO_STATE_ALL);
5
6 glClear(GL_DEPTH_BUFFER_BIT);
7
8 redraw = false;
9 al_clear_to_color(al_map_rgb(255,255,255));
10
11 draw();
12
13 al_restore_state(&state);
14
15 drawHud();
16
17 al_restore_state(&state);
18 al_flip_display();
19
20// draw():
21
22void Renderer::draw()
23{
24 ALLEGRO_TRANSFORM trans;
25 al_identity_transform(&trans);
26
27 setupProjection(&trans);
28
29 glm::mat4 mat = camera_.getMat();
30
31 trans.m[0][3] = mat[0][0];
32 trans.m[0][1] = mat[0][1];
33 trans.m[0][2] = mat[0][2];
34 trans.m[0][3] = mat[0][3];
35
36 trans.m[1][0] = mat[1][0];
37 trans.m[1][1] = mat[1][1];
38 trans.m[1][2] = mat[1][2];
39 trans.m[1][3] = mat[1][3];
40
41 trans.m[2][0] = mat[2][0];
42 trans.m[2][1] = mat[2][1];
43 trans.m[2][2] = mat[2][2];
44 trans.m[2][3] = mat[2][3];
45
46 trans.m[3][0] = mat[3][0];
47 trans.m[3][1] = mat[3][1];
48 trans.m[3][2] = mat[3][2];
49 trans.m[3][3] = mat[3][3];
50
51 al_use_transform(&trans);
52
53 glEnable(GL_DEPTH_TEST);
54 // Accept fragment if it closer to the camera than the former one
55 glDepthFunc(GL_LEQUAL);
56 glEnable(GL_CULL_FACE);
57 glFrontFace(GL_CCW);
58 glEnable(GL_ALPHA_TEST);
59
60 if(!setShader(SHADER_DEFAULT))
61 {
62 NBT_Debug("failed to set default shader");
63 }
64
65 glBindVertexArray(vao_);
66
67 resManager_->setAtlasUniforms();
68
69 for(auto &it: chunkData_)
70 {
71 ChunkData *cd = it.second;
72
73 ALLEGRO_TRANSFORM ctrans;
74 al_identity_transform(&ctrans);
75 al_translate_transform_3d(&ctrans, cd->x()*15.0, 0.0, cd->z()*15.0);
76 al_use_transform(&ctrans);
77
78 cd->draw(&ctrans, look_block_info_);
79 }
80
81 glBindVertexArray(0);
82
83 glDisable(GL_DEPTH_TEST);
84 glDisable(GL_CULL_FACE);
85
86 resManager_->unsetAtlasUniforms();
87}
88
89void Renderer::drawHud()
90{
91 if(!setShader(SHADER_ALLEGRO))
92 NBT_Debug("failed to set allegro shader");
93
94 if(!resManager_->getAtlas()->getSheet(0)->alBitmap())
95 NBT_Debug("no sheet bitmap????");
96
97 al_set_projection_transform(dpy_, &al_proj_transform_);
98
99 ALLEGRO_BITMAP *tex = resManager_->getAtlas()->getSheet(0)->alBitmap();
100
101 al_draw_bitmap(tex, 0, 0, 0);
102
103 float x = 0.0, y = 0.0;
104 glm::vec3 camera_pos = camera_.getPos();
105
106 const char *block_name = look_block_info_.state_name != nullptr ? look_block_info_.state_name : "unk";
107
108 int dw = al_get_display_width(dpy_);
109 int dh = al_get_display_height(dpy_);
110 al_draw_filled_rectangle(0, dh-36, dw/2, dh, al_map_rgba(0,0,0,200));
111
112 al_draw_textf(fnt_, al_map_rgb(255,255,255), 8, dh-26, 0, "Block: bi:%i:%i:%s x:%i, y:%i, z:%i", look_block_info_.id, look_block_info_.data, block_name, look_block_address_.x, look_block_address_.y, look_block_address_.z);
113
114 al_draw_textf(fnt_, al_map_rgb(255,255,255), 8, dh-12, 0, "Pos: x:%.0f, y:%.0f, z:%.0f", camera_pos.x, camera_pos.y, camera_pos.z);
115
116}
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mind78
Member #15,802
November 2014
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Ok, you are all allowed to mock me relentlessly I thought something looked a little of with my description there. The thing is... setupGLstuff(); while(1) No matter what I put in there, of course it won't work when it doesn't even gets called. Realized just now when I was reading these posts It works now anyway, I have to reenable the culling for the GL and that was in the part that didn't get called
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